I was installing a wet room recently and the customer came to me saying his boiler kept blowing a fuse. I had a quick look and told him the fault lay with the gas solenoid valve. The boiler was an old (17 years) Worcester Bosch. I couldn't find a GC number on the valve so I gave him all the markings off the valve and the name of a corgi to help him out. Bosch were quite helpful but hats off to www.gasbits.com who correctly identified the valve and had a replacement on his doorstep next day. Quite competitive price also.