OK Guys, just to wrap this thread up I bit the bullet and purchased a new Radiator to fit myself.
The fitting wasn't without a few issues though.
The overflow bottle was pretty manky so I carefully removed it to clean it up. Not carefully enough as I dislodged the top pipe which came off in my hand.
Sacré Bléu !!
No probs I thought. I'll lift the tank to see where it attaches then re-attach it.
Sadly it appears to disappears into the bowels of the engine.
Off with the Air box to see where it fitted. I couldn't see any place obvious.
So a quick trip to this forum took place to solve the mystery. Knowledgeable ST users will be way ahead of me here.
Turns out the top pipe of the overflow/Reservoir bottle is just a breather pipe that discharges to the ground.
DOH !!
Back on with the airbox and tank. Fill my new Rad and reservoir bottle and a quick engine run.
All seems OK so a shakedown run in the next few days should complete my latest adventure.
Thanks again for the info that's available on this forum.
If I had done a bit of research
before lifting the Tank/Airbox I could have saved myself an hour of
"spannering" but hey ho.
Live and learn ....