One of my DD's peers travelled to G&L from Teddington, only two changes but an early start, and they regretted that decision and the journey. It really added to her levels of fatigue. They have busy tiring lives at these schools especially if she is a serious musician, why add to that needlessly? I have actually known girls leave G&L and LEH in year 9 because long journeys had become too much. Added to the tiredness was the fact that they were doing the journey alone and none of their peers lived locally.
Just one morning's encounter with the journey and the Hammersmith roundabout convinced me that the Hammersmith schools were not really an option beyond Richmond.
Whilst I know that some girls chose G&L over SPGS, LEH because of the bus network actually has a bigger catchment so you will get some very bright girls who cannot access the Hammersmith schools.
Not that it tells you anything LEHs results tend to be infinitesimally better than G&L generally, don't go on last year's A2, it was a blip due to the cohort. The destinations are down to the girls, G&L have a Central London catchment so their girls tend to favour US universities more but girls do go to Yale etc from LEH, especially the rowers, plenty of experience should you need it. Again don't go on last year's destinations. The new Head at LEH is making a lot of changes for the better and is well liked which will make a difference as well.
They are both schools that enable bright girls to achieve their potential so it should come down to your DDs gut feel about where she will be happiest, taking into account a journey that she will without doubt, when she has a lot of homework for public examination and after school activities, come to hate?