After a couple of months playing around with this menu trying to simplify it even further, I have had a breakthrough thanks to an email from Ioan Sameli who had taken one of my menus and produced a variation on the theme, and now with THREE sub levels.
This menu made use of something I had not come across before (you learn something new every day) and that was the use of :hover pseudo-class with no preceding element and when used in this way it appears to apply to any element in the particular style structure.
So here I have made use of this method to have just ONE cascading style sheet and just ONE style for all browsers, no separating the a:hover from the li:hover.
This is probably as far as this can be taken .... but you never know.
The CSS is so simple now and can be seen in the page head along with comments so that you can alter it to suit your requirements.
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