None of my 3 nearest stations have better than 95RON. There is a Shell station 12 miles away & Tesco 18 miles with 97RON. I have only put 97 in my M3W once & after that difficult cold starting & wont idle. I think this was coincidence when engine warning came on. Its sorted now with new plugs (they looked fine to me with correct gaps) new fuel & air filters.

Tim