Guilty for me, there's too many elements to the overall picture for any other verdict (I'm nervous about a "not proven" but can't see a majority going that way). The DNA and fibre evidence require a lot of mental gymnastics to explain away, while the defence witnesses seemed to be there purely to drag RM and TM through the mud and make them look unreliable, which does nothing at all to discredit the CCTV timings, the DNA, the fibres, etc etc.
Put it this way, in order for him to be found not guilty, the jury have to believe the accused is the unluckiest lad ever, just happened to go out for cannabis in the middle of the night, to end up having a secret rendezvous with a young woman who's so attached to her boyfriend that she's incredibly jealous of boyfriend's daughter (yet happy to have an affair on the side), he then completely innocently came home, had a shower, went out clutching some clothes, came home without said clothes, went out and came home again, all in the small hours of the night, for completely innocent reasons. And this is the same night his nefarious affair partner has decided to abduct and kill Alesha.
Meanwhile, clothes he'd lost in the sea several days earlier, resulting in walking home naked through a whole village who never saw him (and he was seen wearing similar that night) wash back up and coincidentally match fibres found on Alesha's body. A knife matching his mothers' kitchen block is found on the same beach. And somehow his affair partner has taken a condom full of his DNA and used it to frame him, while somehow getting fibres matching his clothes (which he'd lost days before meeting her) too... yet not getting any of her own DNA into the scene.
Probably missed a few details in there but yeah, I can't buy it. My ONE question mark is over how Alesha came to be out with him, as I do find it hard to understand how that could happen, but then we've never learned the layout of the flat, for all we know the door of her room could be right next to a stone staircase which doesn't creak! I don't think that's enough doubt for a "not proven" though; the CCTV timings, fibres and especially all that DNA tells too much of a story.