Vibraplane

Cello,in response to your question,it would seem that the Vibraplane would work best if the flooring was wood.Both my friends had a non suspended table(like yours)on a wooden floor.Hence,the Vibraplane was a clear improvement.
I don't remember if your flooring was concrete(I think it was solid),but it would make a difference,as I'm sure you know.If so,you may be better off with a "solid dense" platform,like somethong from SRA!

Is any one using a HRS isolation split base (as recommended for the Brinkmann balance TT) with a Simon Yorke 7

I would think that the Vibraplane would work just as well on a concrete floor as it does on a wood floor, The difference is that on a concrete floor there are less floor vibrations that you would have to deal with so there may be less expensive options to get you the proper isolation.

Redscouser - I use a Neuance Platform used my Simon Yorke S7. The platform sits on top of a set of Aurio MIB 1.2's. This seems to work nicely for me. My floor is concrete. I'd love to try a Vibraplane, but the sheer weight of the beast is a deterrent for me.

What isolation have folks found to work well under a SImon Yorke S7, other than a Vibraplane?

I don't see the advantage of an additional active,air suspension,if you have a high mass table on a concrete floor.Provided it has a superb stand.I could be wrong,but wouln't the solid stand/high mass table better be able to evacuate resonances?