Traditionally, we treat the summer holiday as part of the Summer term, that means the summer term doesn’t end until 31st August (a convenient date). Therefore it follows that Easter holiday is part of the Spring term, so the Spring term doesn’t end until the day before the new school summer term. The Autumn term is 1st September to 31st December.
In OSM, it’s important to have consecutive terms (no gaps) and that all the youth sections use the same dates. For adult sections it’s not so important, but terms still need to be consecutive, so we run one term a year, 1st January to 31st December.
You can find Bracknell school terms on the Bracknell Forest web site.