boiler servicing how often?

[John.Stitch]

I installed a Worcester Heatslave combi 12/14 two years ago in a garage/toolroom conversion where i now live.
I had an Worcester Bosch engineer call out after 3-4 months to check the settings as it was putting out a lot of smoke. He checked and adjusted the settings with his specialist kit.
The boiler is never on for long periods because the insulation is so good in the house. It comes on for maybe 5-10 minutes in the winter every 30 mins in the evening, on less than 1/2 power, and for 15 mins for the hot water in the morning.
So given that Worcester clean and adjust the burner when they service them and check other settings, how often should it be serviced?
The price for a service from them is £100, so what kind of local service engineer should I look for and any ideas as to how much please.

 

[wilhelm]

once a year. if for nothing else, to check the flexi fuel line. cos when that developes a leak... . you'll wish you had had it done. actually i say check, i change 'em every year. and i dont care what folk say.

shop around. i wouldnt balk at 100 squid. so long as its done properly.