Fitting heated oxford grips. So, I've removed guards and ally type ends. Screwed into bar is an internal threaded insert, which looks a hex socket but not sure ? Has anyone got the size and type of this ? A 12mm alen wrench is fairly snug, Throttle side grip was bigger internally so went right over, but on clutch side it's same diameter as bar, and this insert has a bigger circumference so will need removing.