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.