Sime 60 stopped working (both central heating and hotwater)?

Sime 60 heating system (circa 7 yrs old and annually services incl. some parts replaced in recent years) installed in the loft has been working quite well and providing uninterrupted..In recent days it has been receiving prolonged use (especially with the cold weather) e.g. on for 14 hours non stop intermittently.

Went up to examine the heating system in the loft and noticed that the pilot light is off while the thermostat is set high and both heating and hot water settings are switched to the on position. Could there be a simple solution to this problem? Would appreciate comments/input.

vee ess
December 2007