Engine quietly cutting out

[Denise Rennard 0]

Hi, does anyone have any experience of a 2007 Touran quietly cutting out while driving? It's just been serviced and has plenty of diesel in the tank, but it just cuts out and drifts to a standstill. Once stationery, it will start again without a problem, but the fault reoccurs when driving again. The AA thought it might be a faulty cam shaft sensor, but the garage said the code for that isn't coming up as a fault. It's been a brilliant car for years and this is pretty much the first time I've had problems with it. Any advice would be greatly appreciated before I'm charged more enormous labour costs at the garage.