A4 (130 BHP PD TDI) 2003 - Engine Cut Out

[Swynne]

My car has for a mysterious reason just decided to cut out without any warning.
The engine turns over continuously yet I cannot get it to start having been no trouble whatsoever.
The car is well serviced and I have maintained oil levels etc as required.
I'm at a loss to understand whats happened after the car was running without missing a beat.
Is there a cut out switch that needs reset as I'm told this may be the problem after the car was subject to a rear end shunt a week previous which dented the boot lid.
Any info out there as to any other owners suffering this problem would be seriously appreciated as its parked near home and I don't want to try bump starting it even though its a 6sp manual

Thanks
Steve