@Tony Cook I doubt the difference between Sport and M Sport ride/handling is hugely different. In fact I was told it was minimal. I’ve never known any BMW to be wallowy so I wouldn’t worry. If the Sport is slightly softer than the already excellent M Sport, then all the better in my book! I did insist on driving the 35 as opposed to the 40 though. Sport models seem to be thin on the ground. If you look at the used car locator, there may be some Sport models near you, but they are more likely to be the eDrive 40.
Having driven probably over 100 BMWs of various shapes and sizes, I would agree with you that the standard suspension is a better bet than the M-Sport suspension. As you say, BMWs are never wallowy, and I always find the standard suspension fine for ‘keen’ driving, but a bit more forgiving on rough surfaces. Whilst most BMWs with M-Sport suspension are OK, the ride can be compromised when combined with larger alloys. I once drove an X3 M-Sport with upgraded alloys and it was an absolute bone shaker, yet I drove a 5 Series M-Sport with the standard (albeit still quite big) alloys and it was still limo like, like the non M-Sport 5 Series that I had at the time. The unfortunate thing is that the M-Sport models undoubtedly look better! The experts tend to recommend M-Sports with the addition of adaptive suspension, so that you get the best of both worlds, but that’s often not possible on the smaller BMW models (and certainly not using Motability).