So I guess all things considered, £549 although expensive, is not exceptional.
Am waiting for a price from Sigma Performance. They quote 2 valve servicing from £275 +VAT +parts inc. lapping valves, etc.
With the bike being worth so little, I just can't justify spending £549 on a service.
My Dad was a mechanic for 20-odd years - looks like I might have to bring him out of retirement!