Poterton kingfisher II RS80 will not fire, pilot is lit, but will not fire ?

If there is nothing at all, it could be something as simple as the thermocouple.
If the thermocouple isn't conducting heat to the gas valve, then the gas valve won't open and allow the burner to kick in.
They're anything up to £15 at any Parts Center/Plumb Center,...far cheaper than a gas valve which could cost up to £200.
Good luck

Northern Knight
February 2010

Need to know if power going into boiler if not external control fault
If power at boiler suspect gas valve

a
January 2010