Update!
I’m very pleased to say that I eventually managed to get my hateful car booked in with MG Portsmouth back in July to get the very temperamental air conditioning fixed and to (at long last) get a software update (I was still rolling around with R33, as MG Southampton had told me on two separate occasions that no software updates existed for my car

).
To my great satisfaction, after having the car for 3 weeks while they carried out troubleshooting, they not only fixed the A/C (it needed a new compressor) but they also updated the software to R63, and my god what a difference it has made!
I can honestly say that I no longer hate the car. A good number of the issues on my original post (top of page 1) have now been dealt with, which is of course great news. I can see why people with newer software than R33 were much happier with their cars than I was, but it’s left me rather confused…
Why on Earth would MG release a car that was originally so shockingly bad? It seems to me that they must have done very little testing indeed, and instead just rushed it out to market and crossed their fingers. The car is now very usable, and I only have fairly minor complaints, but having had it in such a terrible state for two years, and having had to fight battles with both dealerships and MG UK to get it fixed, I still will never get another MG again. It’s very clear to me that they’re an untrustworthy manufacturer who cares more about quick profits than long term customer loyalty.
Fingers crossed my final year with the car doesn’t throw anymore issues my way…