I am revisiting this thread with the hope to gather some info on my bike.
The frame & forks are built with 531 Reylonds tubing. There is a sticker on the seat tube that reads "Handbuilt and Brazed in England for FW Evans by ORBIT". The bike is built with a 21speed RSX groupset (Deore LX rear mech) that as far as I know it was intoduced in 1997. Cantilever brakes, Brooks saddle, Mavic rims.
The bike was given to me by an old guy when I used to work in a bikeshop in London. I have been using it the last 3 years and the only thing needed so far was some lube in the sticky left hand shifter. Everything else works fine.
Any additional info from you would be much appreciated (year of manufacture etc)