I'd say if the video were true, wales needs new police.
Al1 registered a domain for his website, should have his full contact information for everyone to view, he could "hide" his information by having his hosting company fill out the form, but the police just need to ask the hosting company for the real information and voila.
Even then, the domain points to an IP, which points to a server which can be easily backtracked.
Fortress used a youtube account, google logs IP's from logins, which they could just use to go to his house. On top of that England has the most extensive system of CCTV cameras in the world, I would be very surprised if he didn't get caught by one when going to the bar. Then there is also the bus camera when he went to wale's tale, he was carrying a shovel to a sparsely populated area, I'd say it would be pretty damn easy to spot him. Especially since his video gives him a time and location for when he posted his video prior to going in the field.
All this with just a cursory examination. So either the perpetrator of this is the best super-criminal the world has yet seen and scrubbed everything from every database (a large country might be able to pull this off, even then its pretty iffy especially in the UK), or there is evidence lying all over the place.
Plus a single stab wound? A lot of times they can identify a body just with a single bone fragment, let alone his full face + dental records + personal belongings.
I'd say pretty poorly thought-out hoax if the creator of that video intended it to be "real".