OP, sounds like your DD goes to a lovely little school, you're very lucky to find such a place in London, I spent ages looking in West London for my daughters back in the day! Where about are you at the moment?
On the Godalming front, you pretty much have access to all of those schools, as like previous posters have mentioned they all have bus routes. However, I'm not sure about St.T's so you'll have to check them, but I reckon they must. Are you moving to the area from London? Is Godalming set in stone, it's very accessible, but obviously lots of other places about, some better for specific schools?
So, disclaimer, on the school front, I only have the second hand and "WhatsApp group" stuff from friends at St Cats and Priors Field. But I do have family at GHS and Tormead, with my nieces.
St Cats, as has been mentioned, has had a rough ride in the last 18 months. They're not so great covid response is not a state secret in the local area, plus the issues mentioned by the PP are also out there. That aside it still gets great results and has beautiful country surroundings to boot. If your daughter is up for it, she will do well there academically, but with pastoral care there in such a spiral dive (from a PR viewpoint, anyway) I'm unsure as to how supportive they will be if your daughter encounters issues as she progresses. Im sure some parents will confirm, deny or clarify.
Priors field might good choice, its less academically pressured as far as I know, they don't get the best results and are considered the easy-access option girls' school in the area. That being said, they have a countryside campus and there's obviously less pressure. A PP mentioned that they have good support in place for those who need it and did a good job at their online provision, so could be worth a serious look.
GHS, if you daughter has it in her, it a great school. My younger niece goes there. It is one of the countries best girls' schools in fact. You'll need to be confident that your daughter is up for it though, as although there is no direct pressure applied, the indirect pressure of being around so many smart young ladies will permeate her, especially if she is a little behind the curve. Also make sure they know her background with regards to dyslexia and will make provision accordingly. But if she has it, its definitely the top choice.
Tormead is where the other niece goes. It has always been considered as the "academic school" you go to if you're worried you can't get into GHS or St.Cats. Its also been seen as a really top, solid, academic back-up for those applying to girls' schools from the local preps. This year however I have heard that the level of interest in places has been high, it's definitely one to watch, like the PP said. I think its a great school with even more potential. Alongside its "academic backup" reputation, its also regarded highly for its pastoral care, especially in the prep-school and by the exam year students, inc the sixth form, where my niece is. Extracurricular wise, they have always been slightly;y behind "generally", but they are GB champions in gymnastics and recently they have started a number options such as rowing, alongside cricket, rugby, etc. The girls have jumped on it and my niece, as an example is loving the rowing. There also seem to be investments in pastoral care staff and facilities.
I think your best bet is go see them all as quickly as possible. Especially if your committing to a house move? If you have already committed to Godalming, then rest assured, comments aside, we are blessed with some brilliant girls' schools in a beautiful part of the country, and wherever you pick, your daughter, I'm sure, will thrive!
Good luck!