R-Class: petrol into diesel engine...now it's gone crazy!

[Sym7]

I have a diesel R-Class. First time in my life I accidently put petrol in the tank (thankfully only £20 worth because pump was so slow and I was in a rush). I started the car on tick over while I went to pay (so kids could watch their DVD). My wife came running in and said she had to switch the engine off because the car was making an awful sound (so we caught the problem early). The man at counter of the filling station called someone on our behalf to "fix" the issue. He turned up in 20mins and drained the tank (and put some cleaning fluid in too). Luckily £20 of fuel only partly filled one side of the tank (it's shapped like a saddle over the drive shaft). I started the engine, it banged and clonked for a few seconds and then ran smooth as ever.

Now, here's the problem: as I left to go down the motorway all warning lights came on. No ESP, no ABS, no Cruise Control etc etc. Mercedes service people told me this would go away after the computer sorted itself out after a number of restarts. Well, that was Tusday and the problem's still there.

Anyone suggest anything? Any clues why this may have happened? Maybe someone with a similar experience....but please don't tell me this is going to cost me a bag of money!

Thanks.

Edited by Sym7 on Friday 20th August 15:36