I have been given a laboratory stirling engine made by G Cussons of Manchester. It is a marked P5688/2 and looks much the same as current P5691 but without power supply. See:-
I'm in two minds as to whether I want to hang on to it or not, so may consider a swap if anyone else desperately wants to own one of these and has 'something interesting' to offer in exchange.
Couple of pics on webshots - end of 'all hot air' album.