I have regularly donated inventory to them in the past- I think I wrote about it extensively on TOS. I came in contact with them through The Prince’s Trust who I think they’re tied up with. They have a big warehouse in Telford, one many private logistics companies would dream of.
I believe the charities that use them do actually pay for the products, albeit a massively reduced/token amount, and this is where the income comes from. My gripe would be that although it is expressly forbidden in their terms and conditions presumably charity workers with access to their inventory of dirt cheap goods do re-sell the stuff on car boots and ebay which is problematic.
It would probably raise a lot more and be more useful to charities if the companies involved cleared their obsolete inventory themselves and have the money to charity