I think its the shifters that are the problem . The one for the front mech seems like there is something stopping it shifting all the way . Can they be taken apart or will I cause more damage if I try ?
I had those shifters on an old Dawes I bought a while ago, and I had similar shifting issues.
A bit of Googling seemed to suggest that they are prone to getting gunked up internally. I blitzed mine with degreaser and got them spotless, but TBH they never worked particularly well despite this. You can remove the front cover but be careful as there is a 1/4 turned spring behind it.
I wasn't that fussed as I ultimately restored it back to factory spec and as such re-fitted downtube shifters to it.
When it comes to trying to repair them,
AASHTA, the picture in that link illustrates the potential problems you'll face!
There was a guy, (on
ebay I think), offering to refurbish old shifters, but IIRC he was in the US, and I wasn't sufficiently interested in pursuing that option.
Good luck whatever you decide.