I've had a lot of problems with UK airlines and non compliance of speed restrictions as well, but since I'm in a terminal environment is usually the opposite problem, with them slowing down way too early.
Its gotten to the point that I don't even bother with them anymore. As soon as they slow without telling me (after I have instructed them to maintain x speed), I just vector them out of the sequence, and make them number last. If they slow on final below 170 more than 8 miles out, I'll have the tower send them around instead of the aircraft behind them.