This would be the first year for stage 2 tests for the Sutton girls grammars. I think, the tests would be similar to the boys. See all the threads on Wilson's, Wallington Boys and Sutton Boys and as well as Tiffin Girls.
There are several responses from Ladymuck and would be very useful. One such is this.
Well for English, it is simply different - it is a writing exercise. The maths is trickier because there will be various 5 mark questions. Strictly I don't think they will go beyond level 5 topics in maths. In terms of writing not only will some children be writing at L6 standard, there will be a few at L7 standard. Certainly last year it appeared that the English paper was the one which differentiated pupils who got a place, and this year WCGS and Wilson's have put even greater weighting on it.
In one sense you are over the worst: I think there is more "technique" in answering the multiple choice papers. By this stage you've covered all the maths, and in terms of writing the main bit to practice would be to check writing in a 20 minute, 30 minute and 60 minute timeframe.