MBWorld.org Forums - C200 AMG CDI Auto intermittent power loss

I purchased my car as above, new in November 2016. It currently has just over 5000 miles on the clock. Since April 2017 I have suffered problems with no acceleration from a stop at traffic lights, roundabouts etc. I put my foot down and nothing happens initially, then at the second or third attempt, the car goes. I have also had a similar experience when attempting to overtake. I now drive in fear of a rear end shunt!
No warning lights show and nothing is recorded on the computer system in the car.
It has been with the dealership three times. It is obviously under warranty. Initially I was told it was a 'known problem' and the ECU was updated with new software. Within a week the problem returned.The dealership had the car four days, no fault was noted despite regular usage by staff who put in excess of 100 miles on the clock.
I am currently out of the UK,having had the car returned two days before I left. My Nephew has since used the car on my behalf...he has had the same problem, on one occasion almost being in collision with a bus when power went as he pulled out! The car has now been back with the dealer almost a week, and will be with them a further three days. Their attitude seems to be if the problem does not manifest itself and nothing is recorded on the management system whilst they have and use it, there is nothing wrong with the car and it may be down to the way it is driven!. My nephew and I drive in completely different ways. Personally I have had a licence for over 50 years driving a huge variation of vehicles, including HGV's!
As you may imagine I am thoroughly hacked off with both the car and dealership, to be honest I am almost wishing I had never bought it.
I would appreciate a response from any other owners with the problem and also any suggestions as to what the problem may be to give me some ammunition to use with my dealer!