The speeding awareness course in North Wales which is one of the worst places to get caught speeding are generally offered up to speeds of 40 in a 30 zone. It depends on several factors though, for example, previous convictions or if you've been on a course in the last 3 (or is it 4?) years. Only Scotland does not offer a course these days.
BTW, When I got done for speeding some 22 years ago, I was caught by a police motorbike who was hiding under a bridge with a hand held meter. He caught me up and showed me the reading, it was 80.8 (in a 60 zone). When the summons came through from Shropshire it had been rounded down to 80 mph.
Pete