I have a 2010 Octavia VRS CR 170 , I was driving it friday evening, running fine, drove 12 miles, pulled in for fuel, filled up then jumped in to start it, it started no problems ran for a second or two then cut out, tried it again, same thing, no untoward mechanical noise or engine lights, called the RAC and the Aux drive belt has partially disintegrated, part of which has got trapped around the cam drive pulley. The scan read that there was a misalignment between the cam position sensor and the crank position sensor. Question is whether there would likely be any engine damage, given that it started and ran a couple of seconds, sounded as smooth as it usually does, then the ECU shuts it down. The Aux belt went about 6 months ago, was replaced by local garage and has gone again which is a concern in itself, this needs investigating obviously but given the engine ran smoothly whats the likelyhood  it could just be a case of putting on a fresh cambelt and re-aligning the cam and crank?

.......£350 later and the Aux belt had slipped and failed due to a failed Aux belt tensioner failed spring, had this replaced and the cambelt tensioner replaced, all good now, had only slipped 2 teeth so no engine damage thankfully! thought I would post this up as a warning, anyone with a high mileage TDI, its worth changing the Aux belt tensioner when doing the Aux belt as failure could quite easily have taken out the engine had the cam slipped at speed, part of the Aux belt had been carried by the cambelt and wrapped around the cam pulley.

sounds good advise, what mileage does the car have on it you just say high mileage and that can mean different things to different people ?

If it Is a repeat failure of the tensioner, then get the rest of the aux belt system checked as well. You may have a failed over running alternator pulley which will cause the tensioner to jump around, leading to  it failing prematurely.