As @bradders guessed, Micheldever Tyres (part of the Protyre group), located between Basingstoke and Winchester at Micheldever Station. Used them for many years and have a good relationship with them. I’m off there this morning to change over the now shagged after Donington Supercorsa SCs with the Pirelli Superbike slicks they sourced for me. Andy
May as well give a recommendation while I'm here. EMJ Bike Tyres is a mobile supplier/fitter based in Bristol. Lee will supply & fit either to a loose wheel or deal with your bike. Top bloke and operates a good 20-miles or so radius from base.
Thanks for the recommendation Btw have you tried Metzler Roadtec 01 - they are very good dry and wet road tyres on the Monster 12