All of the UK Crestworth Lanterns I've seen take a bayonet bulb, (B15 base), not an SES (screw in) base. It's possible of course that your bulb holder has been replaced with a screw in type. The bulb in your photo is a halogen, at the moment there are still plenty of 40W traditional incandescent bulbs on sale on ebay/amazon, althogh they are existing stock, they are no longer made, so stock up if you need them.
that bulb should work but you may find it over heats, i use halogen SBC baynet 28watt = 37watt and they run my vintage bases fine, your has had a alternative bulb fitting installed
© 2023 Created by Mark Goo. Powered by