to AK for his advice and PeteB for unexpectedly turning up to assist.
Long story short, Rob now has new calipers (which took 2 hrs to bleed) and I have 320mm discs and Rob's old calipers.
The adjustable forks however
, had a bent caliper bracket on one side, which left me with squishy brakes and wobbling disc. So std ones back on.
Its been a long, frustrating and exceedingly expensive day. But our club members came up trumps again and at least we will be out there tomorrow
Thanks again guys.