Fixed my radiator leak, but may have inadvertently caused further issues
After Googling, I settled for "Liqui Molly Stop Leak", first attempt resulted in it still leaking (booooo), so I did a complete radiator removal (along with some of the pipework) and pressure tested the rad - leak found!
I decided to try the leak stop once more, and this time it worked! Hurrah!!! But... I noticed that the temps seemed to be a little high - town riding @25 air temp was in the high 80s or low 90s. And a long run on Sunday resulted in 107 in an air temp of 32 (these were 'in town' figures).
So, sadly, this stop leak may have clogged up some of the water channels/veins in the engine
Next mission - flush this stop leak out of the system; so far I've seen a suggestion of first running the bike with a water + liquid dishwasher detergent, followed by a distilled water and diluted citric acid powder, then a flush with distilled water... might check that a bit more; than I did with this stop leak.