Well, a hour to service a boiler would be about right in my estimation, yes it can be done quicker, but as I posted above, if correct proceedures for soundness are followed it ammounts to nearly 20 mins. (which I observe)
ie. 5 min stabilisation 2 min test let by, 2 min test soundness, on exit 5 min & 2 again....
Add to that you, open, remove the burner, clean, check all connections, remove fan and clean, re assemble,.....lets say a safe 15 mins
Fire the boiler, test your max/min pressures, then give it 5 mins warm up,
perform a gas rating.......lets say a total of 10 mins
Then also do the 'BG' FGA, another few mins.........lets say 2
OK now we are up to 47 mins, again you wirte it up, have a quick check of a few rads (looking for sludge problems etc) maybe top up system pressure (as you have noticed usually in the hot press in Ireland)
Then address your customer, make sure they are happy and know how to use the appliance correctly or any other concerns they might have....I think I can safely say an hour.........would be VALUE for money
I am not ready to run in and out and provide half a service.......
Also, you refer to 'BG' service, FGA only, seems to be comming back into vouge with the HE condesing boilers, as with some you are obliged to replace seals etc once you have opened the burner chamber / heat exchanger.......manufacturers instruction say FGA is enough, unless safety ratio is above 0.0040 then full strip down required, I would see the first part as a 'mini' service or safety check and charge accordingly