The Marist Sunninghill or Hall Grove Bagshot

[JOJOHNSON23]

Does anyone have any knowledge of these two schools and which is better academically?

Many thanks.

OP, that's a curious choice for comparison. One is Roman Catholic and single-sex. The other is multi-denominational and co-ed. One has boarding. The other does not. Etc.
There are loads of good private schools in this area. What are you looking for and what made you select these two? I don't think either of them are necessarily best of breed.

Single sex or co-ed, I'm not worried and also not worried about faith or not. I don't need boarding facilities. I'm just after a really good school with an excellent academic reputation - if I'm going to pay I want the best!

anyone?!

Of those two, Hall Grove.