Hi, I can only offer an opinion on CLSG based on first hand experience - can't really comment on G&L - due to proximity, wasn't really on our radar to do further research - it would seem to be a great school based on results, reputation etc. but can't add much more.
My daughter is currently in year 9, and honestly we couldn't be happier with the school. She has an approx door to door commute of 45 mins to an hour (based on luck with trains, dawdling with friends etc.). We moved from an independent through school (large green campus and grounds, great facilities) which was much closer to home, and where she had a place for the senior school. To be honest, the first time we visited the school, I questioned the commute, and even when we got to the building I was feeling apprehensive, but that all changed almost immediately when we entered, met some of the girls and got a feel for the school.
First of all the experience over the last 2 and half years has been fantastic. Saying the school is very academic would be correct, but then that would paint only half the picture. I think you have to make a clear distinction between what you would call a pushy environment to one with high expectations - and the important thing is those expectations are not limited purely to academics, but also the co-curricular side of things. The girls are encouraged to participate in drama, music, sports and many other activities. Yes, the campus isn't sprawling green fields, but I think they have extracted every bit of value they can from the space they have, and actually results in some quite innovative spaces for performances, sports and other activities.
If I had to list the different activities she has done over the years, it goes on and on - School Play, Choir, Robotics, Tennis Team, Athletics team, Cricket team, Inter-school entrepreneurship case competition at the LSE...it just goes on and on, so any perceived lack of facilities has absolutely zero impact on opportunity.
In terms of academics, it isn't easy - very frequent testing - but it seems to be done without a cut-throat approach - with strong support from teachers, lunchtime clinics for optional support. In year 7, we even had a weekly call with a year 11 student to help in languages.
And the pastoral care has been excellent - strong support on study skills from a dedicated team, fantastic support for mental health and wellbeing with a full time counselling service.
Overall we couldn't be happier - like I said, I don't want to comment on other schools without first hand experience, but it ultimately comes down to fit which for us, CLSG has been brilliant. Happy to answer any specific questions.