so no reply yet, and unfortunately i have not managed to solve the problem yet.
Basically if i send inside an email {token_whatever}={contactfield=whatever123}, this will generate exactly what is being passed through in the payload as well as whatever123 value from the contact card, however the moment I put this into an href tag the only thing that still shows up is the {token_whatever}.
I have tried with {{token_whatever}}{{contctfield=whatever123}} - no joy
I have tried with single parenthesis instead of double in the href tag - no joy.
I am guessing this is probably something to do with GrapeSJS stripping something or messing with something along the way.
Still holding out for a solution from someone here.