I agree - there isn't a great choice in the UK now that the Chrysler Voyager (and related vehicles) are no longer available in our market. My issue (one of several) for importing from the US/Canada is that they are left hand drive - it just wouldn't work for me.
I opted a number of years ago for a right hand drive (UK spec) Chrysler Grand Voyager adapted by Bekker. It's the most accessible car I have ever owned, and works well with my frontwheel drive Balder/Etac powerchairs which have the auto-lockdown feature. However, it is also by far and away the most expensive car I have ever owned, needing continual upkeep from the start (electrical, mechanical, bodywork - we've had all the issues!). It has alwawys been well looked after and has low mileage (45k miles in 11 years), but it eats money(!).
I'm not quite at the point of replacing it but have been keeping my eye out on what is available - and, like you, I've not been too impressed with what's on offer in the UK at the moment. Very small rear access vehicles or large vans, but nothing really inbetween - especially not side entrance ramps.
The offerings from Paravan (German company) look promising, but again for me the issue is that they are left hand drive
Cal
Paravan
https://www.paravan.de/en/home/Ford TourneoParavan Citroen Jumpyhttps://www.paravan.de/en/product-solutions/driving-with-a-disability/paravan-citroen-jumpy/Peugeot ExpertLanciaHyundai