My only contribution is to comment upon how incredibly expensive they appear in comparison to their non-adapted counterparts.

I suspect that you'll need to go down there, armed with all the necessary disability aids, and assess the ease of access and egress of each vehicle. Peugeot Partners have certainly been around for long enough to prove their reliability and there are plenty of people who rate them (I'd want one with aircon though with all that glass).

From the selection they have, i'd recommend a Kia Sedona for the reasons highlighted above. Other brands (vauxhall Easytronic, Volkswagon DSG, Skoda DSG, Fiat Comfortmatic, Renault Easytronic, Seat DSG.) are highly problematic. Better off with a torque converter automatic. Search the internet for any of the gearbox makes i mention and you'll find a host of repeat issues, expensive repairs only for issues to arise again. I'm not sure about the Vauxhall Zafiras they have for sale, but Kia seems a safer bet.

My parents had a Peugeot Partner under the Motability scheme. They chose it because of ease of access into the front seats - they are a good height, and the sills aren't too wide (the latter can be a bit of an issue with some cars if you have restricted mobility). My father bought it after my mother went into a care home. It's now six years old and has been totally reliable. It has only covered 22,000 miles in that time, with mainly town running, although my father at 84 is savvy enough to give it an occasional motorway blast.