Yes, executors can charge for expenses but, apart from obvious major items like the probate fee, flowers and maybe the cost of getting certified copies of documents, I think it just doesn't seem right to start charging for every penny- petrol costs, phone calls, paper, stamps. I have been an executor 3 times and I have never bothered with expenses.
To save family disputes in your case, pussnboots, i would ask for the breakdown but would probbaly only make an issue if the expenses include a charge for time and/or seem unreasonable and come to hundreds of pounds.