I have had my Polecats years and they have been faultless, however of late I had been having problems with being unable to lock/unlock them,things came to a head a couple of weeks ago, so here is the simple fix:

Remove the central rubber Ferrell, and thus withdraw the lower leg. On the end of it is a white split plastic cone, looks like a 12 bore plastic wad.

This locates on the square headed bolt which screws into the end of the pole. It should move freely but as it is steel and screws into aluminium it corrodes and seizes so preventing the white cone expanding and hence it wont grip the inside of the upper pole.

Apply WD50 to free, then remove bolt and lubricate with copper based anti seize grease and reassemble. make sure bolt screws in and out freely.

Wipe the whole leg with a cotton rag, apply TINY smidgen of oil film, then re assembly pole leg.

Takes a couple of minutes and will transform sticking/sliding Polecat legs.