I gotta say, I can see it from both sides. No one likes paying over the odds for something, but convenience comes at a price.

Whilst the fitting fee's might be "free" (which they aren't; they're included in the yearly membership), you can't expect to pay shelf price for something not on a shelf. The fact is, a man came to you, supplied and fitted a part, and got you on you way. Yes, it was more expensive, but that's the cost of convenience and service.

A Burger King meal is double the price in a motorway service station than it is in a high street restaurant. A pack of fags from the vending machine in the pub are a good deal more than they are in the corner shop (and you typically get less in a box from the vending machine). A special delivery post option is about double what a 1st class option would be. You could go hungry and carry on driving till you get to a town before eating at Burger King, rather than pay the extra at the motorway services. You could jump in the car or walk to the nearest late night shop or petrol garage to get a full 20 box of Benson, rather than paying the increased cost (for less fags) and stay in the pub all evening. You could just send it 1st class, and hope it get's there the next day, rather than chose the special delivery option at the post office : You pay for the convenience and speed.

Way I see it, you had two choices - pay the inflated cost of a replacement part (fully fitted, and guaranteed) and be on your way with minimal bother and lateness (to what was actually a very important event) or you could have been recovered, completely FOC, to a local garage, or back home, and set about buying a starter motor yourself, fitting it yourself (with no guarantee) or pay a local garage an extra fee to fit it (with only a labour guarantee) and waste a whole day, or more, and miss a very important event.

I know which I'd choose...