I've since learnt it is a Walter Rohrl car. One of several he used for Pike's Pike and other events. Word is, the new owner is trying to get it road compliant so it can be used for on road event use. I'm assuming Targa perhaps.
The owner is a moderately well known local motorsport person. Tarmac and rally. I just haven't yet got permission to identify him. Needless to say, he has been around a while and has an impressive classic car collection. I'm hoping for a face to face soon.