Indeed, it's very 'brand focused', lots of parents love to be able to mention their school name at the dinner parties and functions! I've experienced it myself, it's incredibly cringe worthy.
Be under no illusion though that GHS is a good school, as in it produces good results, thus the product you are buying delivers. Whether they do that by actually teaching the kids well, or by simply starting with a very clever cohort, creamed off, as a result of a self-fulfilling brand, well, the jury is out!
The other schools though, fish from a different pond, arguably a less creamed-off pond, so they have to work really hard to recruit, educate, keep happy and deliver excellent results for these little fishies.
If I was school hunting, I would be looking for the school working hard to not only attract my DD, but look after her, keep her happy, educate her and get her some good results, even if it is only to compete with the other local schools! Value add.
and.....not the one that delivers on high entry requirements and trades on a brand.
My opinion only!
That said, you asked about PF and TM? IMHO both great options.
Ps. PP I agree on the guildford co-ed void, but Tormead is a successful girls school that always fills its year groups and has been over subscribed in year groups before, so, why rock the boat? Remember of course unlike 'boys only' education (which is on its death bed), girls only is thriving and actively sought out! I actually wonder if one day RGS will go Co Ed....... but god help the first girls co-hort, who would want to be part of that! Lol