Thats.... Steep. Tbh. Although all things are relative, ie, best quote we had was £2400 fitted. Similar situation to yours.
But when compared to what we actually paid, with numerous extras, as we know a heating engineer(Biker, trained plumber, sparky, gas safe or whatever it is) that original quote then became expensive compared to what we actually paid. Which we believe to be a good deal, although still plenty of room for mark up and profit for two days comfortably. Dont begrudge that at all, did a great job.
Condensing boiler re sited in the garage. Megaflow(?)
Power flush etc
New wireless stat, Drayton
New cotrol unit, honeywell
Monsoon water pump to boost water pressure from loft tank
Larger hot water tank to cope with geater flow.
Rad valves in major rooms x5 (honeywell being cheapest that are worth having)
Plus ph balance system at a differant address.
2,200 total partly cash payment. As a guide... ?

Bit far from the Forth though.
But does explane why hes so mega busy and difficult to get hold of. Hes flat out.