Apparently, if you damage your car on a speed hump, then the speed hump is technically illegal.
You are not allowed to obstruct vehicles on the Highway. So if something damages your perfectly legal vehicle (if it was illegal your MOT tester would of told you), then it is an obstruction.
Report the hump to the Police. If the hump is on private property, send the owner a bill, and follow it through with a County Court Summons.
Remember to take pictures of your damage this evening. (and then find two friends who can be witness - i actually saw you go over the bump ;-) )
Tinman