So problem fixed! Star diagnosis came back with " Gear Change Implausible, check gear box oil"
Gearbox electrical plug was leaking, so that was replaced and 2 liters of oil added.
(last garage checked but didn't pick up on any of this)
Also slight misfire on cylinder 4, just needed the cap reconnecting
Now it runs like a dream.
Cant recommend John Haynes garage enough, great customer service and price
Independent Mercedes Specialists | Worthing | Sussex | Goring
Good to hear you have it all sorted Stuart, with minimal issues.
Only thing I would add, in your position, given everyones input here, and my own thoughts, I would have had the garage decamp the transmission fluid, fit new filter and new oil throughout the box, it needs doing anyway, you have a very nice car with extremely low milage, you need to keep it spot on, should you sell the car in the near future, it may be a neagative not to have done this, at this moment, when it was a very easy to do item at this time, with very little additional expense.
I look forward to seeing your car sometime, sounds a very good one.
Regards R