Hmm. Firstly the free childcare thing is based on what the highest earner makes, so you could be on nothing, and if the partner got over the limit, then no one gets free childcare.
Once you've got children it becomes much much harder to progress, my professional career has certainly stalled. And once you've done a mat leave, and then maybe gone to 4 days a week, you start to become the lower earning partner and then when school holidays, sickness, fucking school settling starts, you become the default parent because you can't afford to lose the other person's salary/piss off their boss. It's totally unfair of course, but something I heard repeatedly from professional friends too (doctors, solicitors, civil service, vets...)
Is the commute the same? The next level up for me would be about a 25k pay rise, but would necessitate being in London all the time, so the train fares wipe out most of the increase (and add a lot more hassle and time).
Check the mat leave policy, though that might red flag you unfortunately.
Otherwise it comes down to whether you want that extra time at home, or are very career driven. It's probably not a big enough pay rise for me that I, personally, would do it. Especially if you are moving from a type of' switch off' at the day's end role, to 'lots of unpaid overtime expected', because on top of normal additional hours there's a huge amount more stress (I know, I've got an 'always on' job.)
How flexible are your current place? That's one of the main things that keeps me from changing, as I can work flexi, from home quite a bit, decide my own schedule.