BAD NEWS:
I'm using Dreamweaver CS3 and the property inspector in this version doesn't seem to have anywhere to set these parameters for the Flash movie.
GOOD NEWS:
Having looked at the code there seems to be only 3 places that WMODE could be inserted - so I stuffed it in all three places and behold the menues are now visible in Firefox, Maxthon, Chrome, Sarafi and Opera.
BAD NEWS:
The menus are still being obscured in IE9 ...
I guess 5 out of 6 is reasonable - just a pity the duff one is IE as I've heard that rather a lot of people use this !!