I've got a collection of working SATA HDDs which I need to get rid of (1x320gb, 3x500gb, 1x1tb) I thought I'd donate them to charity but I can't find anywhere online to do that, they all seem to want whole PCs.

Any ideas for a UK charity that I can give these (possibly other stuff too) to?

I can't imagine that there are any charities that would want that. I'm surprised you even found charities that want whole PCs. Do they specify what kind of PCs?

I was under the impression that schools and charities didn't want old computers anymore. It's hard for them to refurbish a bunch of one-offs, especially when they can get professionally-refurbished systems bulk-ordered for very little. I could order a dozen Core 2 Duo Dell Optiplex computers for under $1000, and they'd come with fresh Windows 7 licenses. I think a charity would consider that a better use of their time and money, rather than taking one of my client's ancient XP towers they've had since 2002.

Goodwill (here in the US) uses the sales of their stuff to hire folks and keep them employed. They take computer stuff and build working systems.

Link for these refurbished comouters?

Windows ... oh well...

Here's where I occasionally get refurbs for clients who want a cheap computer. They sell Macs too.