If you're on Facebook, there's a private group called Golden Opportunities that is for breeders, rescues, etc. to post retired show dogs or older adults for sale. You have to answer all the questions to get into the group, but it's a great resource. Adults pop up regularly several times a year for sale.
Our Rescue co-oordinator is looking to rehome 5 adult Basenjis at the moment.
I'm sure @Zande is helping all of you, but I remembered each of you as being in the UK and I wanted to make sure that you saw this.