I'm really not too sure how long it sat still - it's 10 months old. The one actual physical fault the dealer found was a clogged urea filter which apparently can be to do with a car being sat on the forecourt a while.
It's a lovely car and in the 24 hours of pain free driving I had before the errors started it was a pleasure. Unfortunately now my main emotion is worry that it's going to be a pup with recurrent & impossible to solve electrical faults.
I guess time will tell & hopefully sooner rather than later, if this problem does crop up again.