Yes but not with a seven. On a rally to the Pyrenees in 2009 a pal with a Pembleton Brooklands tore the centre out of his clutch plate and 3 years ago I did the same with mine. Cured with a new "sprung" clutch plate.
I had a job to dissuade the RAC call centre not to send an inspector to find out why I had lost motive power. Fortunately after 20 minutes of explanation they just sent a recovery truck and I only had to wait one hour...

This looks very much like a fatigue failure,caused by the plate being under stress.
The photo shows no marks on the boss, but is there a possibility that it has been in contact with the flywheel nut? I know its an unlikely long shot, but I can't think of any other reason that would cause such a failure.
J

Location: As far east in Kent as you can get