99% of the time the boiler is fine but occasionally refuses to switch back on when the 'stat calls for heat. I've found the best way to deal with it is to isolate the boiler from power for 30 secs. to 1 minute then switch back on & all is well.
My question is; is this a for-runner of impending control board doom or is it merely a board glitch.

ivor problem, October 2012

You can try by replace over heat and temp sensor they easy to change you do not have to drain boiler not expensive ,more likely it's PCB

ltd, October 2012

Replace PCB you get cheap on EBay

ltd, October 2012