HOW DO YOU FIX THE BAXI BERMUDA 50/5?

I have today ,28/01/09 just had an engineer try to start our 6 ish year old Bermuda back boiler - packed in a couple of days ago. Engineer serviced it, put it back together, worked once then when he tried switching the thermostat off and back on again - what a surprise - nothing - silence and just the orange LED turned to red. As of tonight it's still just the gas fire that works! Told it may be the PCB !!!! thing is I can't find the manual to find a "fault finder" as there's another smaller led behind the main one and that's flashing orange (2 flashes, pause, 2 flashes, pause etc) Any ideas as it's getting colder in here...

Iain.
January 2009