So I found a few problems with the rear brake. The pads were almost worn out causing the piston to come out too far and stick. The needle roller bearing in the pedal was gunked up and almost seized causing a sticky pedal and the hose from the reservoir to the master cylinder had worn through on the engine. All cleaned, greased , repaired and new pads fitted. System bled and now I have a back brake I hope. (Not ridden yet)