TAs are like a sticking plaster. The small school my daughter went to had lots of TAs too, because the school generally couldn't meet sen needs, so lots of children got ehc plans with TAs as the infrastructure in the school wasn't suitable.
Meanwhile at the huge school, it was harder to get an ehc because the infrastructure allowed the school to meet a lot of sen needs without ehc plans and TAs.
The big school had three emotional support workers for starters - small school had none. It had a huge playground and it paid for youth workers to work with certain children during breaks and also take them out of class for extra sessions.
It had a wide range of teachers, every year they had new staff, and there were head of year posts, so it meant that ambitious teachers joined for promotion - at the small school, the staff had been there for over 20 years and there was no movement, no new ideas either.
They had a big sen team and had seen such a wide variety of children and behaviours and were able to use this expertise. The small school never seemed to know what to do. For example, both schools had girls with severe eating problems. Small school did nothing, didn't even notice what was happening. Big school made appropriate arrangements - they had staff available to do it.
My younger daughter had a lot of additional needs and would have been given an ehc and her own TA at the small school. She didn't need it at the big school. She did need one for secondary, so we got that organised at the end of year 6.