Sorry this has taken 3 months to do - finally got the hang of using my little digi-cam and how to get my PC to talk to it for videos.
Thankyou Nick, Dave Stew, Eric, David D and Spin for such kind encouragement.
Here is the first vid. of a run. I tried using a much larger heat sink on the tube with Propane torch. Ran for a bit but didn't seem to like it. Probably not enough heat in the displacer?
Here is a slightly longer vid. using the original heat sink (sorry about the messy heat sink compound - it gets everywhere) - the engine runs and runs, provided the torch heat is kept up. (I was grinning at the time).
Peter