I took mine into the MG garage first thing yesterday (It's about 20 miles from home). I had a courtesy car and it meant I cold spend time with the local peregrines albeit the temperature was rather cold!). By 3pm I'd heard nothing and chased them. Basically they's not been able to "recreate the problem" - I realise the staff there are just using high level language to move conversations along but the fact that I'd had to chase them over several hours to tell me what was going on and then they effectively claimed they'd replicated heavy rain on the Cyberster did rather irritate me.
So the upshot is they still have it and have escalated it to the top MG UK technical lead - they claim MG aren't admitting others have reported this issue - I find this unlikely given this thread although it may well not be widespread but will depend where the car is parked when it is raining hard.
I also reported that the seat doesn't always go back when exiting - Again they couldn't replicate it!