Chris
European Aviation in Bournemouth have a fully operational 727 sim, but I am not sure if they have UK TRTO approval. Cheapest route for you will no doubt be somewhere in Florida.
I see you also asked on the African forum about 727 ops... try Interair in Johannesburg, they operate a couple, also Transafrik in Angola if you want something more, shall we say, adventurous
I've flown with a few ex-727 drivers, they all agree its an awesome aerie!
Good luck
http://www.eaac.co.uk/flight_training/simulators.jsp