Hi Ross and welcome to the madhouse that is EuroKClub! Again!! I'm sure we have a feature that allows you to contact us to give you the account details....
Anyway, the overheating is, without a shadow of a doubt, a clogging/clogged radiator. This is a really useful feature of the K which gets you a new radiator every few years and it only costs about £450 a time.
The clogging is normally on the outside. The front, lower corners of the rad get full of shite because the front mudguard is rubbish for a sports tourer, more useful on a weekend warrior machine.
The solution is lots of soaking and gentle washing through from the back of the rad until you can see daylight through every pore in the matrix. Allow a whole day for getting it as clean as possible and hopefully the overheating will disappear.