Thanks fellas
Yep Dennis -that worked. I exported it as an "old-style" AVI and Registax just sucked it straight in.
I have a Scopetronix afocal adapter sitting in the cupboard I'd forgotten about - and I tried it this morning to discover that the alignment is going to be perfect for this camera to line up with a 1.25" EP mounted on either my home-made 80mm or the 66mm Petzval.
I hope the weather is OK tonight, like it was last night and I'll do some M42 and Moon stuff with it.