Removed my grip and switch assembly last night as the starter button was a little more difficult to push than normal, cleaned it all out and thought that while it's off I may as well clean under the throttle grip.
Was quite a bit of dirt and general grime underneath which soon cleaned off with wire wool and Autosol, little bit of silicon spray on both the inner grip and bar, reassembled and all feels good, will give it a ride out today and check if weathers ok.