My son (5) is a bit nerdy, I suppose (loves Space, Top Gear, meccano etc and probably goes on about them at school a lot) - I have found myself going from chatting to half the class parents to barely managing regular conversation with a handful.
Our school is in NW London and is apparently outstanding 
I am actually quite sociable as a person and feel I have a lot of life experience and good conversation to offer. However, if somebody I have been friendly with for the entire duration of ds' life can exclude him from a picnic in the park to which they have invited most of the class (whilst giving out the invitations in front of me), then I simply cannot be arsed to even say hello to those parents tbh.
I do so occasionally, mind you, if we meet face to face or they pass our house and look towards me as I put out the rubbish
. However, that's it and neither DS nor I could care less about their play-dates, gossipy little intimacies etc. I have risen above it and actually feel that I have evolved as a parent as a result whilst they remain shackled by their silly little intimacies and need to be validated and accepted within their clique.
Admittedly, I did feel upset about it in the beginning as I felt that DS might be missing out on the social opportunities afforded to DD- I could not understand how well-educated, well-informed grown ups in their 30s and 40s (who work in 'nurturing' fields such as teaching and social care) could actually behave like that. But I grew a thicker skin quite quickly and realised that I was actually better-educated and successful than they were (as well as younger
), so therefore I did not need their validation.
Whilst DD benefits from having a close circle of friends (mainly made at Brownies for the short time she attended), DS does not have the same social needs and expectations.
The London school-gate scene is a strange, strange thing - I personally find that for a multicultural city and barring the odd exception, there is very little real socialising between people of different origins and classes - they stick within their groups (the Brit caucasian 'posh' lefties, the younger chavvy white parents, the Polish mums, Chinese, Indian, Pakistani etc). I sometimes think that most of these parents must live and work in multicultural settings, yet this fails to translate across into improving integration at the school-gate.
I also considered moving very early on. However, as with your child, DS is settled, enjoys going to school so surely that is the most important thing. I do intend to move but it is no longer remotely connected to the attitudes of other class parents.