Thanks for your compliments guys, In answer to your Q's, its not the original paint, it was British racing green originally, the previous owner had it painted in this pearlescent light blue, I was going to get it resprayed back to original but to be honest I quite like it this colour. I have some decals from Lloyds and one day I'll send it off to Mercian for a proper resto job.
I can find little about Ernie Clements frames online, theres this on Classic lightweights. Its a really nice frame though. Skinny stays and hand filed lugwork, investment cast fork crown tho, which makes me think its an early 80s. And no serial no.
I agree the bottle cage is out of place, i'll have to source a period one some day, it is handy for pints of milk on the way home though.
Youre right the 42t chainring is a bit high for where I live, I recently changed the block to a 13-24 which helps.
Its still an ongoing project really, I recently swapped out the rear mech and shifters for (Purists cover your eyes) 6 speed DA 7400 SiS which works great in a bid for rideability. But rest assured I still have all the SR bits in safe keeping.