Also going to assume Southend High School for Girls and Westcliff High School for Girls here, if only because we are local to schools in the vicinity of each other with those initials.
But also from the WHSG more popular with OOC thing. And the being influenced with the league table position thing, which is tbh much more an OOC thing when it comes to looking at the schools. I'm not sure how it can take another 50 minutes to get from WHSG to SHSG, though , so assuming completely different bus routes?
Our DD actually attended both - SHSG to GCSE (after most of year 7 at another school, having failed the CSSE test initially), then WHSG for A levels. Her main reasoning apparently being that a twenty minute walk from home was better than the same walking time in total plus seven minutes on the train. Four years after leaving WHSG, (six from leaving SHSG), it's her SHSG friends with whom she socialises when she's back here.
If local friends are a factor (for you), then surely a local school where you actually live, not one fairly distant grammar school or another, is the answer? Yes, the journey time to SHSG is significant, but you must have decided, back last October, that 'Grammar School' was the thing - knowing that so much time would be spent travelling there and back, there was no obligation on you to name SHSG on your CAF at all. But you did and your DD was eventually offered a place and you chose to accept it - and she says that she is happy at the school. She can always move to WHSG for A levels, if she wants to. Or to a school more local to where you live.