Traded my ‘15 MG3 on their GS demonstrator about 7 years ago. MG3 had sprung a leak on the clutch hose so I drove it there sans clutch and was treated respectfully and swiftly. Seeing the GS was tempting so I did a fairly good deal. I was invited to the ZS launch in ‘17 and was mightily impressed over the GS, smoother, softer and plusher in every way. Was too soon to buy one but I bought a mk2 1.5 last year on the back of that test.
A year after that I sold the GS due to a job change/pay cut and they didn’t want it back, fair enough. I did find them easy and pleasant to deal with though the service centre was quite a walk from the dealership. If they are still MG approved I’d be tempted to go there, they’re only 3 stops on a train from here so I can leave it at my leisure. WLMG are much closer but have no transport links. I prefer to leave the car for a while than sup strong coffee and sit there googling stuff instead of getting on with my day - but that’s just me!