I don't know anything for sure but as far as I understand it its illegal to upload uk illegal content to a server outside UK so you can't get round uk laws using a server outside uk.
What the uk laws are I am not sure exactly I think there are none related specifically to internet so there is no need for a license and whats legal comes down to whats not considered indecent and comes under the obscene publications act which is about 1000 years old.
People say if you stick within the BBFC R18 guidelines you will be ok.. It stands to reason they'd have a hard time convincing a jury its ok to do something on a video but not on the internet but then you don't know.
People say that the police are only interested in child porn, beastiality and stuff, I saw a scat case in the news before too. It seems reasonable they would only want to prosecute people doing fucked up stuff but then this is the UK and you just don't know.
This is a good site I just found:
http://www.allgo.free-online.co.uk/index.html