OK update
Going with the washer theory (thanks for that!)
I looked at the original banana wheelset and saw there were 2 washers, one on each side of the axle, so I pinched those and cleaned them up.
I put one washer on the drive side axle where it seems to be fouling the rear mech converter and tried again.
This seemed to work, I can now tighten the rear QR skewer and all it good and the cassette spins freely both ways.
However, I am not convinced there is enough room for the chain to get by and feel this could now foul the rear mech converter piece, it will be close if passes by.
Some piccies.
I had no idea I was pushing it with a 10 speed, I wanted 11
this is harder gearing than my CAAD 12 and sometimes I am bottom bottom on that thing on the hills and that's 11-28 this is 11-25, so I guess I should be grateful huh if its not a common mod.
There should be a bible to tell you this stuff lol.
Can't thank all of you guys enough for all your help and advice, I'm not out of the woods yet so I will let you know when I break something else
:facepalm:
Oh while am on the topic here, just want to confirm some other things from today.
I orderd 28mm tyres, someone said they might not fit, I can confirm they do fit, however... I have to deflate the tyre to get it out the frame and inflate once the wheel is in the drops otherwise with the tyre inflated it catches the frame and will not come out.
What else... oh yes, weight, I ideally wanted this sub 10kg or there abouts. I weighed it today and it came in at a meaty 10.28kg and I still have brake cables, cable outers, another roll of bar tape (want this to be comfy lol) and some pedals, jeez am almost there huh, pedals alone will put me 10.7 so I am expecting around an 11kg or just over nana and I can confirm the original weight was 12.19kg so I'll have only saved 1kg, shows you how well they did back in the day.
Total cost thus far for everything is about £670, final build price inc bike purchase, powder coat and all brand new components will be around £750 give or take a tenner.
Thanks again fellas for the suggestions, I'd have thrown this away a long time ago had I not had some support and a place to vent my frustration lol.