You would have to be very good friends with whoever you were sharing it with.
Width is very limited and the seats actually sit directly sid-by-side with no transmission tunnel between them. I'm sure adjustments could be made though and headroom isn't too bad. I'm 6' 2" and I had 1"-2" headroom, although the roll cage intruded from the side meaning I couldn't hold my head upright and that was without a helmet.
None of this is any reflection on Gerry's cars as the same would also apply to an original. They are a great looking car though and I could be tempted myself.
Gerry is currently in a pretty acrimonious dispute with Top Gear after they slated one of his Stratos replicas in a feature they did towards the end of last year.
http://www.youtube.com/watch?v=XWfTZGA1VwY