I have been done for 52 in a 30, I belive you have to do 20mph or more to get a summons mines in april, likely to get 6 points and around £250 fine.
Quotes so far seem to push up insurance about £300 with 6 points.
I was done by one of these new " Saftey Camera Partenship vans" hidden after a corner. Just looked like a biulders van until it was to late, been going round that corner for 6 years before hand, the road is way bigger than 30 zone to everyone does 40 on it.