Ok so I finally decided to sort out my annoying parcel shelf that won't stay up (no sniggering).
short solution
a little bit of that sticky back felt, used for putting under furniture does the trick. some amount will need spraping back to get the tension right.
Like so:
Indepth answer:
superglue on the parcel shelf lip doesn't work, neither does hot glue, neither does epoxy and neither does melting plastic onto it, door draft excluder is too thick, and gaffer tape is too thin. I don't think I've ever tried so many solutions to such a simple problem.
short solution
a little bit of that sticky back felt, used for putting under furniture does the trick. some amount will need spraping back to get the tension right.
Like so:

Indepth answer:
superglue on the parcel shelf lip doesn't work, neither does hot glue, neither does epoxy and neither does melting plastic onto it, door draft excluder is too thick, and gaffer tape is too thin. I don't think I've ever tried so many solutions to such a simple problem.