I think I read somewhere their website attracts around 80k different viewers a month. Of course the license doesn't necessarily confirm it's a formality it's going to launch just means they are definitely looking at it.
EDIT: I feel they're definitely a quite large audience that adult swim could attract in the UK, the 14-30 crowd could work, it really depends on what you want to run on the channel. If you go for that market and let's be honest only really BB3 and E4 goes for that crowd, and you could argue both slightly skewed toward the female demograph, theres a potentially large audience to go for and even more now since the demise of Bravo. I feel the comedy market is a little crowded in the UK (Dave, CC, Gold etc) so your going to have to make something different for your channel to stand out, an action block would suffice but I would possibly rule out anime in the short term, I'm not ruling it out altogether but I find it doubtful anime would be on the channel if it was still in it infancy.
EDIT: I feel they're definitely a quite large audience that adult swim could attract in the UK, the 14-30 crowd could work, it really depends on what you want to run on the channel. If you go for that market and let's be honest only really BB3 and E4 goes for that crowd, and you could argue both slightly skewed toward the female demograph, theres a potentially large audience to go for and even more now since the demise of Bravo. I feel the comedy market is a little crowded in the UK (Dave, CC, Gold etc) so your going to have to make something different for your channel to stand out, an action block would suffice but I would possibly rule out anime in the short term, I'm not ruling it out altogether but I find it doubtful anime would be on the channel if it was still in it infancy.