The final hearing, sentencing and the Judge's comments all struck me as odd. To give such a heavy sentence based on the possibility that he may escalate based on his behaviour, seemed to me almost like they were indirectly saying we 'know he has already harmed.' The Police seemed to be certain he was involved with Libby's death. Maybe this was them reflecting that all prosecuting parties were privately and unofficially sure of his guilt, but also sure that they did not have the necessary evidence to fulfil a court process, and gave a sentence reflecting that. It's like when the teachers know for certain it was that kid, but they can't pin it on him, so he gets a term's worth of detentions for some missing homework and being late.
NB: I am still of the opinion that he dumped her body into the Humber directly rather than into the Hull at the boathouse steps. I know it took quite a long time to be discovered in the Humber, but for me there are too many twists and turns, too many snags along the banks, and too many eyes on the river for a body to make it to the mouth of the Humber... at that time the bank was being worked on, in two places I think, and there are two elevated purpose built viewing bridge control rooms across the river between there and the Humber.