Hi.all I have a Thorn M Gas Boiler approx 25 years old,Turned cold water supply off to change tap washer, Turned off boiler on control panel, and turned off electic supply to boiler, but didn,t extiguish pilot light by turning grey gas control button, after tap washer change realised that pilot still lit, but after turning on electic supply and boiler controls as per instructions, main burner will not light, so turned all boiler controls off, electic supply off, and turned grey gas button, since this pilot will light but will not stay lit after grey gas button released, All help appreciated Thanks. 
