Currently on a rip out for a rewire and came across some of these bad boys! Belongs in a museum now I recon. 100W! 

Remember picking up those 1000w lamps from somewhere in Wembly. The G in GES stood for Goliath and not Giant as many thought.
It is not illegal to buy, sell or use incandescent lamps.I got some lamps off amazon recently, did a quick search for ES vintage lamps and these popped up, I fitted them and though wow they dim really well compared to others I've fitted in the past, no flicker at all. Its only when I grabbed one of them that I realised they were fillament lamps and not LED's. Didn't think they could sell fillament lamps anymore.