I had the same trying to trade in my nearly 4 year old Golf and in the end went to WBAC.
What I get the impression of is it’s a chore for the dealer so they really don’t want to know but because Motability say you can use your own car towards the AP on a Motability car but they begrudge buying your car.
Whereas in the OP case the car is of the same franchises, with mine, although the car not being very old at the time, it was a different manufactures car and at first thought that’s why they didn’t really want to know after asking time and time again for a price but now see its simply because they can’t be bothered, much like we get sometimes when enquiring about cars.
Just as a side note, in today’s news there’s talk of massive lay-offs in cars sales personal so wonder if we might get more attentive service now.
One last note about WBAC, they bough my car for about, I would say, £500 or £600 below what I could have got elsewhere but I required a quick sale and the car itself required a service and at least one new tyre so was happy to let a few hundred go as being disabled its a chore to sort that stuff out myself.