So here's my aforementioned notes, most of them are probably rubbish but you never know, something might trigger a memory or mean something to someone. Personally I think whatever happened either happened in her house (why leave her debit cards etc) or very close to home. Claudia taking her phone but not her cards suggests she may have been in a hurry too.
Firstly, I thought I had previously been in the house that Richard Cartwright lived in. I went to a house party on East Parade on Halloween of 2014 (I remember everything though, I'm one of those people who somehow manages to remember everything after a night out), and I did a google search of Richard's house. I was absolutely sure that the party I went to was either in his house or the one next door, however I have since found the house with the party was number 63 (next door to Cartwright's - number 61). If anyone is interested here is a link from a student letting advertising it two years ago, no pictures though but the description may be pretty interesting as they are all pretty similar on that section of East Parade:
http://www.union-lets.co.uk/details.aspx?id=945
Anyway, the houses in that area are pretty similar with the layout and garden, and from the garden of number 63 you could see into the garden of 61 a little bit, its the type of terraced house with a long garden and a long kitchen backing onto the living room. 63 seemed pretty newly done up and is a student house, and I've heard 61 may now be a student house but I wouldn't know for definite. Anyway, it would be interesting to find out who owns it now and if the owner of 63 had some sort of relation to 61 (or if Cartwright had ever had a connection with 63 as he owned and renovated a lot of properties, as I can probably find out more info about 63 and know a little about it and the layout). However, my immediate thought when I saw a relation between this area and where Claudia lived (apart from being obviously close to each other in Heworth) was of the gardens at the back of the houses.
Most student terraced houses I've been in have had the galley kitchens at the back and a tiny yard, whereas 63 (and the houses next to it) had rather large and long gardens at the back, and at the back of the garden of 63 there was a gate out of the garden in the middle of the fence that surrounded the garden. Pretty high fences, but you could see a little bit into the next door gardens, and as the houses and gardens were all pretty similar, I'm sure they were all shaped and designed the same way. Google maps will tell you otherwise (I reckon the pictures are pretty old on there) but when I was there after the gardens there was what I would call a 'scrubland' behind, leading onto the small alley road at the back of the houses that is a dead end at one end and leads onto Eastern Terrace at the other end. It may have been changed now, but I remember I walked down there a few times in daylight and evening and it struck me as desolate for such a small area.
Incidentally, from there you can get onto Eastern Terrace and go past the Co-Op to the houses via the main road, so you can loop round, but it very much reminded me of somewhere I wouldn't like to get lost at night (the streets in York can sometimes be rabbit warrenish and often connect up via alleyways). I thought I might have some photos of the area but unfortunately not really, all I have is a picture of me in Eastern Terrace next to the co op which wouldn't be of much help, but I am willing to have a wander round sometime and check it out again. I wonder if anything was ever checked out in that area by the police, due to Cartwright living very close by, and that also led me onto my next thought - what was Cartwright's relation to the men that were arrested recently (I heard they were in some of the houses he had renovated?) and does anyone know where they may have lived beforehand? I feel that he may have some link to the case but I am not sure what.
Now onto the CCTV - firstly I agree that there is someone in front of the window of that house (I believe it may be 36 Heworth Road) at the top of the screen in the evening clip. I find it odd the police have not noticed this (unless they have and have identified the people living there) but that person could have seen everything that went on (eg. both people in the CCTV clip the police were looking for) and the way they just appear when the dark man (that is what I shall call him here) comes back but he is not there beforehand is odd too. I wish we had the CCTV in between him walking down towards the alleyway behind Claudia's house and back up again to see where they appear from. Rightmove says the house sold in 2004 so those people would still be living there, unless its rented (same landlord though). Another thing I found odd about the evening CCTV was that the police seemed to assume it was a different person to the person in the first bit of CCTV (Cartwright), yet most of us on here identified them as walking in the same manner, with the same lope and stride so perhaps they have something or some technology that says different? There are also those people who walk to the left at the start of the video, I wonder if they have been traced at all.
I also wondered if perhaps the dark man stops, not because he doesn't want someone to see him doing something shifty, but because he doesn't like the person who has just walked in front of him, or that that person could be someone well known in the area as a nasty person? IE perhaps the person in white could be the dodgy one instead of the dark man. At one point when he is stood still it almost looks like he turns sideways to look behind him, but I believe that may just be the way his feet are placed. However, that made me wonder if there could be someone behind him, either someone he was colluding with or perhaps the dark man was just an innocent man and the real killer could have been lurking in the background which is a rather spooky idea. I also thought the dark man might have had the bag with him when he went towards the alleyway, so what was he doing if so? Not collecting the bag, perhaps a burglar (far fetched I know)?
I was recently thinking about the man who turned up at her house a few days before her disappearance - the one who was on his phone when going to Claudia's door that she looked annoyed/anxious about seeing. A few people seemed to think it may have been a surprise and that they may have been on the phone with each other as Claudia was also on the phone however I think they could have been on the phone to two different people, and hung up at the same time as it is the polite thing to do. Claudia may also have looked annoyed due to having to answer the door whilst on the phone, or because she had to hang up quickly.
A couple of last points - anyone else think the straighteners and the hair dye have to be connected? Otherwise it's a massive red herring. How soon after dying your hair can you straighten it? Perhaps Claudia took her straighteners wherever she went (assuming she went somewhere) because she couldn't straighten her hair at home/wanted to straighten it later. Straighteners seem like such an old thing to go missing and suggests she may have been somewhere else staying over -surely if she had just been at a friends then they would have come forward with them.
Also with the left handed smoking man, a few people pointed out quite rightly that just because he smokes left handed it doesn't mean that he is left handed. Perhaps that's a clue in itself though, it could be someone who is right handed but usually smokes with their left hand or someone ambidextrous. Police also found a cigarette butt in Claudia's car which they couldn't identify, however in the news it has been reported that the police were looking for a left handed smoker in conjunction with this - do we think this is due to the supposed sighting of a left handed smoker with Claudia or something else?
One last thing (sorry I've gone on a lot!), it's a little morbid but something I wondered about when the recent floods were happening. If there was a body hidden or buried somewhere (personally I think if there is it must be relatively close to where Claudia lived), would it be possible for the floods and the water to dislodge it somehow? I've also heard a couple of people around York saying that the river may be a good place to put a body but I doubt that a body could have been in there for that long (especially with the floods), without being dislodged. There's also been some talk (for years actually) from people about the possibility of a serial killer in York due to some disappearances and deaths in the last decade or so, however I believe that may be unlikely.
I know York pretty well though, so if anyone wants anything scouting out or wants to meet up and have a chat about all this over a pint (check out the Nags Head maybe?) then I'm up for it.