Thanks Soqili.

After playing around a little more, I arrived at the same decision as you have just confirmed. I imported the same (2 page) AVI animation (with transparency into a second (different ) video NLE and it imported fine - transparency worked fine. (NLE was from Serif). Unfortunately, I use the much more capable Sony Vegas Pro for editing and it fails to recognise the alpha channel. Will have to use Chroma keying for any future work requiring alpha. Thanks for responding correctly and quickly.

Sadler, many thanks for your response, however, given that the NLE cannot recognise the alpha channel in the AVI generated by Xara, I'm left with no alternative than to use the chroma key (unless I can figure out how to export .png sequence as advised in the above thread - no immediately obvious, as no such option within the animation export menu within Xara.

Thanks to all, Duncan