Bilingual school with moderate fees

I assume you're looking in Brussels or thereabouts, right? As far as I know (and we've looked carefully albeit a couple years ago), there are three main options for "moderate" tuition French-English bilingual instruction in Brussels: BICS, Acacias, and the Lycée Français. There may be others. (Less moderate tuition options include the bilingual sections at BSB and ISB).

I don't know enough about the Lycée to recommend it one way or the other but clearly the majority language at the school is French.

Both BICS and Acacias have a STRONG religious component. From what I've seen (BICS especially), I would recommend AGAINST them very strongly unless their philosophy and religious bent closely matches yours.

7th standard what? (as in what is that equivalent to?)
Why does the "basic curriculum" need to be in English?
What language(s) do you speak at home?

Bogaerts International School ?
http://www.bischool.com/en/index

Have you looked at the Verseau? Bit further out towards Wavre.

Agree with the comment about BICS. Very very intense Catholic ethos. We took our son out of there for that reason.

There is a Belgian state school in Nivelles which teaches some subjects in English and some in French.