From the other side:
I was the child (with a scholarship, at an independent school) that was top of the class in everything without breaking a sweat.
I was at a school like your choice 1. Small, friendly, nurturing. No great shakes in league table terms. The headmaster of my prep was horrified when I (my parents) turned down scholarships to other, high flying, prestigious schools to take up the one offered by my school.
I can't say I was extended in every single subject, but I certainly was in the ones I was deeply interested in, and also in the ones where I needed to be (e.g. because of being pushed through at my prep, and skipping foundation stuff leaving gaps in knowledge).
My school ran extra gcse options, just for me, and then again at A level. I was the only pupil in two of my A level classes, something which simply wouldn't have happened at a different school due to staffing/timetabling constraints. Being the only pupil obviously meant I could be stretched and extended, and I was. Lots of reading sideways, extra background. I covered a lot of university level stuff because I was interested, and my situation allowed it.
Don't make the mistake of going purely by track record either. This lowly, non-academic, friendly nurturing school, overlooked by many in favour of the 'better' schools managed a very high Oxbridge application rate in my year (11 out of 48 of us; 5 successful). Sometimes, the 'lower' option is the better one, as it was for me.