Disc shield detach?

[Lambo]

Hi Folks,

2004 MGZT CDTi auto 43k miles on

So driving home a sudden clattering noise like I had run over something then it continues as a horrible 'rotational' noise?
I drove it the half mile home rather gingerly and parked on the drive, had a quick look and can't see owt obvious but someone said it's likely a disc back plate rotted through and detached?
Has anyone else had this happen? common with 3 series he told me?

So I'm waiting for it to stop raining and have a jack up and proper look!

Cheers

Lambo