Sorry its taken a while to reply, ive had my head fully into finding something worth updating with
so if your interested to hear what i found out read on...
I have been round the houses a bit while researching but basically i started to wonder if it was french or just a mish-mash of parts. Bertin was looking likely but i read on a bike technical site - sheldonbrown.com the differences in tube sizes between british and french bikes around that era. After checking the bike turns out to fit into the british category.
Focusing on the lugs, i now believe them to be Haden, british and widely used by Dawes too - classicrendezvous.com
After trawling the net and finding a few images im now pretty sure my bike is either a Dawes Realmrider or Red feather and date it at early 60s. The Red feather used GranSport derailleurs too, which might make it 50s? but then you cant argue with this Realmrider frame...
http://vintagebikecave.com/shop/frb011- ... 57-cm-c-t/ (as seen in attached pics)
Im still wondering about the grease port on the BB and would like to find out more about when these bike were produced. If anyone has info on this please let me know.
Thanks for all the comments, help and info, hope this is useful for others too