You have not given a budget, are you looking new or second hand?. You also have not said what size of car you are thinking about.

Looking at Suzuki, the Vitara is the trendy one, the SX4 S Cross is less so, but has a usefully bigger boot. Ignoring the boot, they are roughly the same size, both are reliable, but neither (as is the case with most Suzuki's) offer the last word in refinement. There is also the Ignis, which, as small as it is, technically is also a crossover. Despite its tiny footprint, clever packaging and height means it is remarkably spacious with four six foot plus adults fitting in with ease along with a decent sized boot. It is also available as a 4x4 using a mild hybrid setup.

VW has a bewildering array of SUV/crossovers. I'd be wary of getting anything second hand with a DSG gearbox, and i'd also be wary of getting something (new or used) with the 1.5TSI engine which has had some teething problems and, so far, seems to be a step backwards from the 1.4TSI which came beforehand. I'd also steer clear of diesel unless you need it for big mileage or towing duties.

Ford are pulling the plug on the Ecosport, no great loss as it isn't that great a car, but they will probably be available for a wee while yet, possibly some bargains to be had?. So for something small, all there will be for the time being is the Fiesta Active. As its name implies, this is just a Fiesta with a slightly raised ride height (+18mm if memory serves) and rufty tufty looking bodywork additions. Ignoring the Ecosport, next up is the Kuga which is a bit of a jump.

Vauxhall have the Crossland X and Grandland X. Both are based on PSA (Peugeot/Citroen/DS) floorpan and running gear. The Crossland X is the smaller of the two being a rival to the VW T Cross, Peugeot 2008, Suzuki Vitara, etc. Nice long wheelbase so plenty of interior space, but slightly akward looks.

If comparing the Vitara, T Cross and Crossland X. The Vitara has the smallest boot and least amount of interior space, the Vauxhall has most, with the T Cross being about half way between them. None of these are bad cars though, best thing to do would be to test drive all three to see which you like best.

Excellent advice. When I bought my current car, people thought I was nuts being my golf bag, trolley, my suitcase and supplies box (all needed for my annual holiday) and asking dealers if I could see if they fitted in the boot without having to put the back seat down.

Some of the them argued that I could measure up only - no good if the boot space wasn't conducive for everything to go/fit in, rather like your mum trying to get into a car that, on the surface, looked easy to get into.

The same goes for the general seating and driving position, where many people seemingly just change the seat front-to-back position when going for a test drive, and then wonder why it doesn't feel comfortable when test driving it.

There's no substitute for a thorough going-over test of the usefullness and ergonomics of a car before driving it at all. That does mean spending a reasonable amount of time, but it's well worth it in the end, especially when spending the highest amount on a purchase (and thus any losses by having to PX it because you hate it after 6 months will be significant) outside of buying a home.

There's also something to be said for cars with sliding rear doors. Many cars these days have very sloping rear window areas and thus getting in at the back can be very tricky. Your experience with the Berlingo shows that even with MPVs/SUVs things may not be much better, depending on circumstance.

I also do find it interesting that designs are far more geared to the young, and yet older people these days are the ones with the money to spend (as much about them being far thriftier than younger generations as the jobs market and the cost of living), and yet they appear to be ignored quite a bit as regards the ergonmoics and practicalities of car design.

Bromptonaut said "Mum's technique was to shuffle up to door, turn around, and then try to lower her backside onto seat. She'd then swing in knees together..."

I think your Mum's technique is probably recommended for anyone disabled. One advantage is that there's no risk of twisting your knee by trying to swivel on one foot. It's possible to buy thin platforms to put on the seat which will rotate to make the process easier. As you say, however, the width of the cill can negate the whole process.

Crossovers strike me as jacked-up saloons. The seats may be higher so you don't have to bend down to get in, but you need to be sure that you can bend your head enough to get under the roofline without cracking your skull. As has been said, a test drive/ride is really important in these instances.