Personally, I'd say it's too small a school. 15 per year - because your year group are the only ones who will be static in your classroom, half rejected as friends as they are boys (my son chose a girl to take to early lunch when he won that as a prize - it's not a given girls will be her only friends, but it is quite likely the class will divide into 2), and you are down to 7 possible friends. Too restrictive come the older years.
We were in a massive school abroad (2500 kids, 3-18), and have just looked at secondaries. Kids from the local 90 place school were overwhelmed by the size (mine werent). I would imagine coming from a school of 90 secondary would be a massive jump.
Bigger schools tend to have better facilities.
Go look, go see, then base it on gut feel if you cant decide!
Personally, we took places at the catchment school for reception, then the only school who had vacancies when we moved for YR/Y2 (and moved them a month later when places appeared elsewhere- the school was awful - no space, no discipline), and again Y4/Y6. I'm possibly not the best to advise..... my oldest has been to 4 primaries, and only one shift was actively our choice..... I'd say look for a school where the head is involved (not shut away in an office), that offers as wide a curriculum as possible - sport, music, languages, arts, science so the kids get to experience it all. Look for kids who are happy and involved in the lessons, look for teachers who are approachable, but in control. Outside space!!!!! It doesn't need to be fabulous, but space to run, kick a football, do a cartwheel.