That's some top-class tail lamp recognition! Thanks GTE4289, you seem to have a knack for these, and all very helpful.
Sadly I can't seem to find a rear shot of the Balzen GT4 (which would be kind of helpful), but from the side profile, Ford Sierra Sapphire tail lights seem to be the right shape.
While we're on a roll, any ideas about the original donor cars for any of the following please; the Brazilian Aurora 122C Turbo, the Covini B24 and T40, plus the Chris Field Austin Maxi-based Aquila prototype, as below; Thanks.