If i'd known it was a leather one i'd have said it was easier to unbolt the handbrake from the floor and stick something long and pointy under the grip sleeve from the back rather than the front to release the internal prong. Glad you got it off anyway.
I've recently been chopping and changing a variety of mk3 handbrakes together, I've currently got a mk3.5 Cabrio lever with chrome button, a leather handgrip from a colour concept i believe and the leather gaitor from a US spec center console modified to fit between the two.