Thanks for the help folks.
I tried again. I held the push button down for about 3 minutes and the boiler eventually came on. After the boiler stopped the pilot remained on.
I'm guessing that this is a badly positioned thermocouple?
Anyway it works as well as it ever has.
I'll get it...
My central heating boiler will not light.
It is a baxi bermuda 552
I found the online manual and followed the intructions.
I turned the hot water control on. Turned the room thermostat right up to about 40.
At the boiler: I turned the thermostat (aka heating control) by the CH...