Ouch!
Oddly mine has just done the same thing and am repairing tmw. The Nuts/Studs are on back order from Seat too which is a pain.
Out of curiousity, is your downpipe/cat the one piece or two piece item?
I'm having trouble sourcing a replacement so just taking mine off, deleting the cat (it broke on the rear connection) and welding in a straight pipe.