The parts are a smish-smosh, so there's not much help there with the age. The bike is worth whatever you paid for it for the seat, the handlebars and the headtube badge, though. The boss on the right fork is for a headlamp, required in England in the '50's and early '60's, so that may be a starting point for identifying the age. It looks an awfully lot like a respray, so the Landar sticker is probably an afterthought...

here's a start

http://www.classicrendezvous.com/Bri...ed-feather.htm

Dawes is still alive and well, so that should make your googling much more interesting...