How much will it cost me to have contaminated fuel removed from my motability car?

i put petrol in my brand new mobility VW i called out breakdown service who towed it to VW . i was charged £225 for it to be drained out because it was my mistake to put petrol in a diesel engine

That depends on how much this has affected your car. So your best bet is to take your vehicle to a garage and the mechanic should be able to tell you how much it will cost to get it sorted.

By the way, how did you get your fuel contaminated in the first place.