Thanks for all your comments - I've been following this case obsessively, to the point of crying when watching T's mother's statement etc, and it helps to feel others care and are interested.
A few out loud musings (sorry if I go on too long!):-
I don't think excess violence necessarily points to a known killer with personal rage. Some of the most violent murders of women are psychopath/stranger killings, eg Anita Cobby.
Also, I don't think we have clear knowledge that there was an excess level of violence. The police statements indicate there was some visible injury, but I think we are mainly basing ideas that the violence was particularly extreme, on T's Dad's comments. If it was my daughter I found murdered, ANY violence would seem messed up and excessive, I wouldn't be capable of distinguishing between my daughter and worse cases, so I don't think we can rely on this poor man's assessment.
Given uncertainty around what she wore - and if police had any idea of what she was wearing I am sure they would have mentioned, to help jog people's memories - it seems she was found naked and her clothes weren't in the area. This may also relate to uncertainties around whether it was a sexually related crime - naked could mean a sexual motive, and perhaps there were no other signs of sexual assault. However, naked could also mean a killer removing and disposing of clothing to remove potential DNA evidence. That is, perhaps no sexual assault motive, just an attempt to cover up a random rage 'snap'. Perhaps this contributed to her Mum's confusion - it there wasn't visible sexual assault, what possible other reason could someone have for killing her daughter on a beach?
This makes me lean towards the stranger killing theory, by a random 'undesirable' on the beach. Perhaps he attempted to approach a pretty girl and was rejected, then attacked her with a rock or whatever in a sudden fit of humiliated rage. Afterwards, he did what he could to avoid detection - removing clothing and phone etc, trying to hide the body. At least in terms of victim profiling (attractive young woman, by all accounts a lovely person, but with the self-confidence to stand up for themselves and rebuff unwanted approaches) and circumstances of the crime (smaller community, woman out doing something casual and normal) this case reminds me of Mollie Tibbetts. Like Mollie, perhaps Toyah threatened the perpetrator with her phone? Took a photo of him masturbating at her or something?
What doesn't seem to fit with the above, as lots of people have mentioned, is the dog. However, it's not a stranger handling the dog that bothers me - i think a gentle dog could be handled by a stranger enough to be tied to a tree, particularly a stranger with adrenalin going etc - but the inconsistency of tying up the dog near her body, YET trying to bury her body for the purpose of hiding it. Leaving the dog there almost guarantees she would be found after the dog was found (as happened), in which case why bother burying her?
So perhaps she WAS buried out of shame by a perpetrator known to her, who ultimately wanted both the dog and her body to be found. Which then brings me back to the most obvious suspect when a woman is murdered. But I suspect he may have been discounted because he was at work or something, as if they are looking for someone for missing clothes/injuries, this would be easy to prove with M. Also, there hasn't been the footage of evidence, brown paper bags etc being taken from M's house. I don't know! So confusing.
I guess I still come down on the side of a spur of the moment stranger killing, who tried to cover it up, but just didn't know what to do about the dog. Perhaps he tied the dog up after the killing - the dog may have been running off ahead when he approached T, and the killing couldve happened quite quickly, then once he'd dragged her up in the dunes to get rid of the evidence, the dog came back and he just grabbed it and tied it to a tree, then didn't know what to do so just left it. Perhaps he only wanted to hide her enough to make his getaway. Perhaps someone troubled/narcissistic/poor impulse control rather than a stone cold psychopath, who wouldve killed and disposed of the dog too.
Either way, I hope this person is caught, and feel such sadness for T's family that this still won't bring her back.
