So who decides how much you are allowed to mark-up on parts?

You source a part from a dealer and it is more expensive than the factors . Or it's the other way round.

Either way you have had to spend time finding the part, paying for 'phone calls and, in the end, the buck stops with you as you have to guarantee whatever-it-is to your customer.

I don't think that anybody reasonable would begrudge you a modest mark-up on a price which the supplier has already charged a margin on to make THEM a profit.

We could not survive on labour charges alone surely?

Steve