I've received a letter of intended prosecution for speeding from my ex-employers. It was a firm with four vans and various drivers, but on the day and time of the speeding I cannot remember if I was driving the actual vehicle. I did drive one certain van 90 per cent of the time, but the one in question is the one I hardly drove. However, my ex-employer has put my name to the police saying it was myself. If that's the case and it was me, that's fine. But how can I go about contesting this?