This school has an online school uniform exchange on Facebook run by the PTA. You will need to request to join as it is a private group. Check the info on the page (link below) for more details. Once you have joined, simply post uniform your children has grown out of that you are wanting to give away, or if you need new uniform, look there first. When you agree to pass onto or collect uniform from another parent, just message them directly to make the arrangements.
If you get in touch but they can’t help you, try one of the Community Exchanges as they hold generic uniform or put a post on our FB group.