Flashing Airbag light ?

[Mr.T]

Recently rear-ended someone at a roundabout, damaging my '05 plate Ford Focus - no airbags went off. All work now completed at the bodyshop, but they're now reporting a flashing airbag light. Never had this problem before the bang, or at the time between the accident and getting the car to the bodyshop. They've had the car plugged in for diagnostics, which reported a crash sensor fault, they've replaced this, and yet the problem remains. They've also said that the accident has not shown up any cable damage. Any ideas ? - thanks in advance.