Intermittent non-start issue.

Ok, so I've had the car foe 12 months and have had this non-start issue occur for the 5th time.
Basically, turn the key and nothing. Dash lights on, everything works - but the engine doesn't start. The immobilizer orange light flashes and that's it.
Now, I've had both RAC and AA out to it and each (different) patrol guy has said: "Oh yeah, I can fix that, very common on these. Give me 10 minutes" ....10 minutes later and it's all back up and running. Though I do have to clear the electric windows fault that then appears (Open & close each window in turn).
Thing is, I know what they're doing - remove battery leads from terminals, touch them together for about 20 seconds, wait for about two minutes and reconnect.
Suggests to me that the ECU isn't clearing processes and is emptied with this earth-flash.
I've had it at my dealer and, as expected, 'No problem found' because there aren't actually any error codes.
Anyone have any ideas I can suggest to them - apart from what I've described?
Cheers.
Oh and it's going in for the 'Door Alarm / Ringing' issue in the morning as well as the recall that was issued last week about the seat belt tensioner.