Engine fault warning message with stop/start

[steround]

Hi all.
First off, this is my first post as I'm new. so apologies if it's in the wrong place or been posted before.

I was experiencing the following;
When I came to a stop and the stop/start activated, I got the engine management light with the message 'engine fault, workshop!'. The negine also seemed to 'run on' for a couple of seconds.
Diagnostic checks at a local garage and a main dealer proved inconclusive.
After a few weeks of driving with the stop/start switched off, I decided to sit down and think about what may be causing it. A friend told me he had a similar problem that turned out to be an ignition fault, not engine fault. I had noticed that my keyfob was not opening the car as it should - it took 2 or 3 tries and fiddling around to unlock it. I remembered that I got a spare fob when I bought the car, so tried it to unlock the car, which it did, so I used it to start the car.
The stop/start works perfectly now, and the run on has stopped. Car is performing as it should in terms of performance and fuel consumption etc, so I'm happy. I reckon this has saved me £££'s as my next step would have been to let the main dealer try to rectify the problem, which would have taked at least a few hours of labour.
Hope this is of use to other B6 owners.