Sleeping together in a car works for a couple but does not for a longer camping trip. One or two nights will be fine and cosy. Depends on how much you are still in love.
Storage space is more than enough if organised well. Behind the front seats is lots of space for bags and gear and even light shoes. Other shoes will find their place in front of the Co driver seat. On the front seats is space for jackets.
I found out that you do not need to sit on the drivers seat. Pushing the seat with hands will switch the car on. Locking from the inner will work from central display as well.
For the light covers I reused PVC foil from an old caravan tent. A crease with velcro in the foil and a magnet will hold it in place. Instead of a mattress we use a futon because it is thick and cosy and follows the shape of the room perfectly.
Our first experience of sleeping in a car was in the eighties in a Fiat Panda for a four weeks holiday in Spain. Worked great as well.
You probably saw how I organised it. Leave the rear headrests and the parcel shelf at home. Push the passenger seat right forward to fit a large Ikea storage box behind it, which contains a lot of gear like bottles of water and the kettle and the airbed pump and the collapsable bucket and crockery - even a tablecloth and dish towels. With the addition of a cape or a shawl on top, it provides just the right support for the head end of the airbed. However, it stops anyone sitting in the front passenger seat unless it's moved while driving (possible, I just didn't need to).
Passenger seat gets the cool box which is plugged in to the cigarette lighter socket permanently. Draws about 50 watts, worth it to keep things fresh. Passenger footwell gets walking boots and rucksack. However if I take the microwave (haven't tried it for practicality yet) that's where that will go. There's room for the rucksack and maybe even the walking boots on top of it. Non-perishable food was in the passenger footwell too, but could also go inside the Ikea box.
Flight bag with clothes and toiletries travelled in the footwell behind the driver's seat or even in the boot area, but was used to wedge the foot end of the airbed in position at night. I often drove with the back seats up, partly for tidiness, partly to prevent things sliding around inside the car. In that case the deflated air bed, sleeping bag, car curtains and flight bag went behind the rear seats. However if I carry a bike then the rear seats will have to stay down and these items will be stashed around and even on top of the bike. The bike will live outside at night.
I find the space behind the driver's seat useful when getting in and out. I can get in by the rear passenger door, sit on the rear seat back, then get into bed. (I'm maybe not as supple as I once was though!) I have sandals in that footwell to put on to get out of the car, and there's room for more shoes if need be. Do you get in through the tail-gate in that set-up? If so, how do you close it? Or is the futon thin enough to make getting in and out of the rear passenger doors doable?
I was thinking that maybe a roof box could be the thing if two people were travelling together, so that enough clothes, shoes and other luggage could still be carried. That is if you live in a country where the MG4 is allowed to have a roof rack!
That's a good idea about using the central display to activate the central locking from inside. I was using a ski pole to operate the button on the door and had forgotten there was a function in the infotainment screen too. Thanks.