"What sort of non faith free or academy school would you want on the site - what sort of admission arrangements - what sort of ethos?"
A consultation should give everyone a say on that. If there was to be a consultation then I would be one voice in that (so let's not turn this into a debate about my choice). However, since you ask, my personal choice would be for a Science & Engineering Academy. At the moment the only school with a science specialism is Waldegrave, and that is girls-only. It benefits from strong links with the National Physical Laboratory in Teddington, which is a world class facility right on our doorstep. Boys can't benefit from that link at the moment. The Government is promoting science and engineering as career choices, because it knows that is the strongest hope for our economy.
As regards admissions policy I think that all schools should have distance-based admissions. When children attend their local schools it builds a strong sense of community, and the environmental benefits are obvious. I realise that can lead to problems with high house prices, but I think that is a symptom of (a) variable school quality and (b) poor affordable housing policy, and shouldn't be used as an excuse to reject distance-based admissions. However, in order to promote the particular specialism of schools I would be in favour of a small (say, 10 - 20%) quota of aptitude-based admissions. So, in the case of my hypothetical Academy, aptitude in science or engineering could be used in allocating some of the places. Aptitude (as opposed to ability) tests are difficult to specify, so I'm not going to speculate on what that might be. It could be something as simple as demonstrating an interest in the subject by membership of an extra-curricular science or engineering club. However, I wouldn't make it competitive. It should be about demonstrating aptitude above a pre-set level, rather than being the best in the cohort (i.e. more like a driving test than a race), with preference subsequently being given on distance.
I don't think a Science & Engineering Academy would necessarily detract from Twickenham Academy, which is a Kunskappsskolan Academy with a Sport and Technology specialism, or from Orleans Park, which is a Maths, Computing & Languages specialist school. I'd like to think that parents would favour any three of the schools based on the aptitudes and interests of their children. Plus, I'd like to think that my school might be attractive to Catholics too, as they'd certainly be welcome.
There now. I'm going out tonight, so you'll have to shoot my ideas down in flames without me. 