I’ve always dropped off my spares to Spokes in Kidderminster part of the https://www.theemilyjordanfoundation.org.uk/
I believe if you leave bike bit at the Kidderminster tip, they are given to Spokes too.

I’ve dropped loads off over time to Recyke y’Bike in Newcastle. They’ve taken everything I’ve taken them even stuff I thought would never be useful. I’ve got my old Stumpy 26er frame I’m currently mulling donating as it’s gathering dust in the loft.

https://recyke.bike/

There’s a big list of places in the comments of this article: https://singletrackworld.com/2021/11/back-from-the-dead-our-bike-shop-doesnt-run-like-yours/

And if you’re in South East London there’s a place looking for volunteers: https://www.google.com/url?q=https://vee-app.net/3PjXsb6dBry9YJKq9&source=gmail-imap&ust=1667906702000000&usg=AOvVaw23lZ5FxnfQcpfj6tOMFmYV

I’ve taken mine to somewhere in Bristol (a can’t remember the name) and also to Julian House bikes in Bath.
Otherwise it’s all stuff that would clutter up my garage and never get used (no matter how well my intentions are)