I agree most cars do have 3 seats in the back but most, if not all, are not that comfortable for long journeys, well not if your the unlucky one in the middle seat.
Until the Covid breakout last March I often carried my daughter and two of my grandchildren in the back seats and there would be hell of a lot of argument as to who sits in the middle seat. There 6 and 9 years old and quite thin so imagine if they were adults and I add, it wasn’t about who sits by the window.
I don’t know about the layout of the cars Lee has listed and maybe the middle seat is OK but my car is an MPV and while that has 30/30/30 seating as opposed to the normal 60/40 arrangement so the 3 seats are the same size its the middle passenger that has to fit in with both of the other passengers if they have extra width in the rear.?
On the other hand its only once a year for you so you could endure for the luxury of the rest of the year.
Keep watching those YouTube video’s, its the only way if you can’t test drive as I too can’t do that, lockdown or no lockdown, because the car needs adaption but YT is a reasonable guide but they don’t always answer or ask the question for your needs and I’ve spent many hours in showrooms with a tape measure measuring the boot floors of many cars but now having previous cars know exactly what is required so I wish you luck on your search.
BTW from one tribunal winner to another, well done Lee, it’s a great feeling isn’t it to hear the judge say “not guilty as charged”.