I can't see anything wrong in that, provided the mark up is reasonable. If you buy a boiler at "trade" price for, say, £500 and sell it to the customer for the "retail" price of £750, that would seem fair and reasonable. But if you sell it for £1000, i.e. the retail price plus a mark up of £250, then that is definitely not fair and reasonable.The mark up we put on boilers, in my case anyway, is to cover the chance and cost, that I may get called out if a fault develops.
The other thing customers do not like is being charged twice for the same thing: a mark up to cover faults which may develop, and then having an amount added to the bill as a warranty.
One question is puzzling me. If a component in a boiler fails while the boiler is covered by the manufacturer's warranty, does the manufacturer pay the labour charge for diagnosing the fault and repairing the boiler or just the cost of the component?
