AFC Club appearently has announced a release of this vehicle:
http://www.warwheels.net/DorchesterACVindex.html The tentative release date was about 2 months ago, though. There's a lot of chatter on various DG's about this "mythical" kit release.
Seems there's also an obscure resin kit available:
http://www.network54.com/Forum/47208/thread/1300097250/AEC+Dorchester+ACV+-+1st+Polish+Armored+Division+-+Gen+Makzec%B4s+staff++vehicle Marco Serra gives an email addy for the resin company owner in his last post in that thread. I'd guess that this kit is no longer in production because of the AFV Club announcement.
It would apprear that Accurate Armour also had one in the works, but dropped the project presumably after AFC Club announced it's pending release.
That's all that I can offer.
The AFC Club announcement and the resin companies' changes of plans is a prime example of how the model business world seems to work nowadays. Announcing releases (but then not actually comning through) really does have some real world consequences for the rest of us.
As Marco said, "good hunting"!
EDIT:
Looks like SKP actually did release their version:
http://armorama.kitmaker.net/forums/190489&page=1Seems there's a fair bit of "contravasie" over the accuracy of the SKP version along with some other heartburn.
Interesting stuff...