There are auction sites that do BT vans and that kind of thing
Advice....
In the past, these were the kind of fleet vehicles to go for, high mileage, well serviced, good price.
No longer. Why? Because BT etc. do not spend money taking care of their vans, they are wrecked by the time they go to auction, BT drivers bump them up and down the kerbs, run them in second gear, slide in and out the driver seat constantly.. And their service departments now work on a minimum.
Bear these things in mind