57 Plate Octavia vRS problems

Hi

I've inherited a diesel vRS as a company car and unfortunately am having some problems with it. I've had it probably 3 months now and in that time the only issues have been a slight hesitation when accelerating out of corners and the 'Control System for Exhaust' light coming on once while my wife was driving, but it was fine after restarting the car.

However, last week the warning light came back on and stayed on - the car seemed to be running fine and I was planning to get it booked in this week for someone to look at, but on friday while driving home (4 miles) the DPF light came on and by the time I got home limp mode had kicked in. I couldn't do anything about it over the weekend as we were away but I took it to the local VAG 'specialist' today (no warranty with Skoda as it has done 74000 miles) for him to have a look at. He rang me after less than an hour to say that the DPF was blocked and he had 'cleaned it as best he could' but what it needed now was for me to take it for a 'good thrash' over at least 50km and that would sort it. I asked him how I was supposed to do that when it was still in limp mode, but he said that would sort itself out upon restarting the engine at the end of the 50km. He said if it didn't fix it then the DPF would need to be replaced.

The reasons for my skepticism are:

1. If the problem was the DPF becoming blocked, surely that warning light would have come on first rather than the engine one? And surely I would have had more than a few miles warning before limp mode kicked in? Is it not conceivable that it's a sensor at fault?

2. A few years ago I took my mk4 Golf GTi to him because it was pumping white smoke out of the exhaust at idle and would barely even run. He read and cleared the fault codes, charged me £30 and told me to go and do between 50 and 100km then come back and have it scanned again. He said he suspected it needed a new turbo because there was a fault recorded that mentioned it (which was actually due to it having an atmospheric dump valve on). I rang another garage who subsequently fitted a new MAF which fixed the problem.

Any advice would be much appreciated, it won't be me that is paying for it so it's not so much the cost that bothers me as the time it takes for him to work his way down a list of possible resolutions starting with the most expensive.