Thanks Alex,

I missed your reply before posting my last message. I've managed to get this
working O.K. using gif adaptive 256 with index transparency on the export.
http://www.magicalwonders.com/rollover/index3.html

There seem to be a lot of different types of gifs! I'll have to read up about
them to see which is recommended for what! Too much choice

Many thanks,

Myles