WBAC offer low prices. You can always do better on a trade-in or selling privately.
I took a car to them to see what they'd offer (I wasn't desperate to sell, which I think many people are). They give the usual quote online and then you make an appointment etc. I turned up and without even opening the doors he dropped the price saying it wasn't what they were looking for but they could organise payment quickly if I went inside.
I know they won't always test drive or thoroughly inspect (would the staff member even know how to?) but this was a joke. It wasn't even a few quid off - it was about two grand off.
I said forget it, and he said he'd call the boss to try and negotiate a better deal but I said no thanks - and he started cursing me for wasting his time.
Sadly I don't trust their figures any more, and when I came to sell the car and didn't want any fuss I went through Motorway and got more than they'd estimated. Car picked up shortly after and money in the account within seconds.
Could I have got more private? Possibly, but I was happy and got more than the estimate (which was based on a huge number of photos and questions and answers to give them an idea of the car condition - something WBAC didn't do when when they had the car in front of them!).