There are a few near-ish to Oxford (each prob an hours drive away), look at http://www.wakemk.com/ http://www.boxendpark.com/ http://www.wmski.com/
Then there's the ones around London (again prob an hours drive): http://www.jbski.com/ http://www.princesclub.com/ http://quaysws.co.uk/
Quayside does have a system 2.0 up and running, but no other cable. The boat riding there is awesome though, so it's well worth the visit.
If it's not gonna cost you a fortune I would def recommend bringing your own board, as the hire boards tend to be pretty basic (intended for beginners really). Hope that helps!