Interesting new point. I took it to a garage to have the codes reset; flagged up 29E7 and 29E8 but only with a 1 time occurrence. Reset them and expected to drive the standard 40 miles before anything came back; at around 30 I found myself on a single track road and had to stop for a lorry. I was pretty quick in stopping and going up on the shifter straight into reverse but as soon as I did the EML illuminated again. This is either a massive coincidence or my 7 series creates an idle fault when quickly changed from D to R pretty much bypassing N. I wouldn't have thought this could trick the engine into thinking it had a bizarre idle but does this add up to any degree?
What does anyone think?