Bollocks, gave the rear mech a service, proper degrease, wash and dry, GT85 all over, lubed the pivot points. Serviced the bearings in the jockey wheels.
All good, double check hanger, all good.
Put mech and chain back on, fed the cable through the barrel adjuster, frayed the bugger.
So having never done internal routed cables before I took it to the LBS. Few days wait, arse. So buy the inner and outer and the mechanic gave me a couple of straws. Tried to slip a straw over the cable to run it through the frame but just inside the guide is a smaller hole the straw won't fit. Ok maybe I'm in luck and it has permanent fixed straws. So took the bit of inner out from chainstay to BB.
Tried to thread it back through as practice. It'll go in one way but not come out the other and it won't even go in from the other.
I'm going to another lbs tomorrow for a red face bail out.