I have had the overheating problem for over 3 years !!, living in london it originally happened when stuck in traffic - boiled over the lot.
took it to major dealer in enfield who said nowt wrong !! - got it home , sat it stationary on drive - 5 mins needle went up , fan came on but temp did not drop, just kept going into red, and boiled over !! - called dealer who said it was 'normal' behaviour for a high performance bike if not moving - pardon me but what crap !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
must admit rad full of grit due to lots of london and foreign trips etc. (couldn't afford replacement at this time), tried muzy fan, silkolene pro cool (prolpylene alcohol high spec coolant - recommended on usa web forum), checked conectors , burped rad, refilled 3 times over 3 years.
now on Isle of wight for 2 years - still happened , recently got complete 'new' rad with fan and sensor fitted - from EBAY usa for £180 , just fitted it , and ..................yippee , temp goes up to mid mark, moves past it, fan comes on temp drops, fan stops etc etc !!!!!!!!!! - sorted
not sure what was wrong, but i suspect clogged rad either internal or external grit (making it inefficient) or possibly slow fan motor - who cares now resolved
hope this helps