VW transporters are chic, apparently, so silly scene tax applies.

Vauxhall did a good sized crew cab type version of their Vivaro van and might also be found in the cloned alternative makes, its also one of the best medium sized for not rusting away before your very eyes, Toyota old model Hiace the best of the lot quality/durable wise but its getting old now.

There are smaller van/MPV versions, some in LWB form ie VW Caddy Maxi, and the usual Berlingo Kangoo Doblo types might be suitable.

Don't discount proper estate cars, but best try and find those with a proper squared off boot section, those that are style over substance fashion estates are little better than hatchbacks, think about Mondeo, Insignia, Avensis, Passat, Superb and an almost unlimited choice from the German marques...we have 3 dogs and our Forester despite being a small car through having a square lump of an estate section has plenty of dog room, sadly not enough rear leg rooms for adults, larger Outback version might be a left field choice if 4wd is of use, note don't touch a Subaru Diesel with a barge pole and petrol versions have a drink problem.

Thanks for that.. took a look at the caddy maxi..that might suit

Pretty much any full sized MPV/people carrier with the 3rd row seats removed/ folded away would do the job. This includes Ssangyong Rodius, Hyundai i800, Hyundai Trajet, Honda Stepwagon, Chrysler Voyager, Kia Sedona, Ford Galaxy, Seat Alhambra, VW Sharan. there may be others I've forgotten.

There are also JDM imports which would include Honda Stepwagon, Honda Elysion, Honda Odyssey, Toyota Aphard, Toyota Estima, Toyota Noah, Nissan Elgrand, Nissan Serena.

But my concern with all of the above would be safety. So unless you were prepared to get a proper heavy duty cage or some kind of partition, I'd be looking for something to keep the dogs completely seperate from the rest of the occupants. Van's were mentioned earlier, but a crew cab van of pretty much any variety is going to be a bag of nails at £6k. Might be a few double cab pickups (with canopy/truckman top) worthy of consideration though, but it would entail some kind of folding ramp to get them into and out of the rear without injuring themselves!.

Update

Took a look at some used T4's ..all were rotting beyond belief

Took a look at zafira, touran and a few other smaller MPV's and they just wouldn't be big enough

really impressed though with the Ford Galaxy and could get a decent one under £5k BUT I have read that you need to avoid like the plague the auto gearbox .. is that true ?