I have a DD in Y8 at G&L. It wasn't originally our first choice school but we ended up choosing it because it is close (and DD wasn't keen on LU). So far experience has been very positive and DD is really loving her time there.
DD is a strong all-rounder - she plays lots of sports (at school, hockey, running, fencing, gymnastics and trampolining - more outside school), does music (2 instruments and choir) and drama (speech and drama lessons and 2 school productions). I think the school is very strong in all three, with something for everyone at every level it seems (think hockey F team in Y7). For drama, there is a director in residence this year. I feel perhaps there is less on offer in terms of visual arts - my DD is only aware of 1 extracurricular club she would be able to do. Lots more academic clubs to get involved with too. Think lots of kids could thrive there.
Head teacher is indeed the softly spoken type but I have found her very warm and switched-on in one to one conversation - I quizzed her quite a lot at our offer holder event and she was very open and straight in her answers! Suggest you attend the event and do the same :)
Other things DD has loved: a super supportive group of girls in her class who all seem to get on (I realise this is of course luck of the draw); lunch (food is very good according to her); and most teaching. I very rarely hear negative comments about school, other than the environmental impact committee not being active enough :)
Some things me and DH like: lots and lots of extracurriculars; broadening access (the "bridge" programme is very good); very good and balanced provision during lockdown (and pretty good "hybrid" provision for girls quarantining at home); school reports focused on what is going well and what is not, rather than grades. I am told by my G&L mum-friends that pastoral care is very good, although no firsthand experience (as in: my DD hasn't needed any special attention in this respect).
What we like less: some of the extra-curricular sports which I would have expected to be free, are paid-for. Fencing, cricket, dance and rowing are all extra (although the extra sessions of the school sports, of which there are many, are not, and neither are eg cross-country running, gymnastics and trampolining). Not sure how that compares to other schools.
Hope the above helps, but if anything else specific you'd like feedback on, do ask.