Chopped up the wardrobe this evening and moved the pieces I still want into the observatory for assembly. Amazingly the workshop looks more empty already.
I also found a suitable 10mm bolt and tried my HEQ5 on the finished pier (the pier adaptor I have is reversible and fits a number of different mounts). Unfortunately the AZ pin that I have doesn’t fit very well with the HEQ5. I might have to make a new one. Strange that the HEQ5 tripod uses an AZ pin that’s part of the tripod head moulding, but the NEQ6 has a screw-in pin.