Not all charity shops will take your bras to be re-homed. But there are still loads of places that want them.
1. Against Breast Cancer – bra bank, raising money for research into breast cancer
https://www.againstbreastcancer.org.uk/recycling/bra-recycling/
2. Smalls for all – distributes underwear to help women and children in Africa and the UK. https://www.smallsforall.org/
3. Oxfam – bras are used for social enterprise schemes in Africa https://www.oxfam.org.uk/donate/donate-goods/what-happens-to-your-donation/inside-frip-ethique
4. Bravissimo & Mind Charity – for every kg of bras a donation is made to Mind https://www.bravissimo.com/bra-recycling/
5. M&S Shwopping – bring old clothing into M&S store for Sparks points or voucher. Items then sold by Oxfam. https://www.marksandspencer.com/c/help/charities/how-do-i-find-out-about-shwopping#shwopping