Thanks just gone out to check brake lights and all are working and as i was sat in the car the flashing light went out.?First thing to check is are all three brake lights working. If all working correctly then the brake light switch may be sticking or arcing producing a strange signal the computer can not read correctly. Replace bulbs as required and get a good quality OEM brake light switch. Not difficult to change just watch for the sharp edges in the area. If you need further info on changing the switch search on here or just ask.