Thanks ASt85, just to reiterate I no longer believe its a misfire, initially the vibration felt like 2 out of the 5 weren't firing but now I'm almost certain I've damaged the input shaft, synchro mesh or the clutch assembly.....
I still have full power and boost and when I drive it gently I can get it into gear reasonably, when I do boost it it won't slide into gear until the revs have dropped
