Keith
Thanks for the tip – you were right (as was the original construction article) Model engineers make things too tight! I disconnected the escapement, took the clock apart and put a mixture of Brasso and clock oil in each pivot hole, reassembled the clock and ran it at bottom speed on the lathe for 30 minutes, the cleaned all up and IT WORKS!!
Hope anyone else with the problem is helped by this so I’ll post it in the thread