I will check out the size of the tank - I have a few spare ones and I know I have an 83 model GS one as well as an MX one so will show him the difference if needed - I was also led to believe the forks were a different diameter ie: 40mm for GS and 42mm for MX.
So thanks for the help so far, any other support is welcomed and those that provided me support will have first option on the bike.
I will go look see tomorrow and make an offer – traditionally I make a viable offer then utilise an agreed method that reduces the offer as we progress ……….(but cant give away all my secrets yet)
If successful I will post some pics and make it available for what I got it for.