OK, I'll jump in here to defend John somewhat. I have seen the car close up and it is head and shoulders above the Sabre MK I in quality and fit. There are MANY improvements to chassis and body in this car. To address the convertible issue: these cars (replicas with fibre glass bodies) never got ANY structural stiffness from the roof. Period - end of discussion. The car is longer and, to suite UK's new regulations, has a hatch back rather than a tilt clip. John said he planned to have insertable top(s) for it. The windshield is standard MK I. (I know because he was using my windshield to test fit in the frame- mine till a corner got cracked out of it.) As to styling, I prefer the MK I myself, but it isn't bad looking either, IMHO.
I haven't talked to John in a while, so I don't know the particulars of his arrangement with Venture, but I know that he was anticipating having to move back to the UK for personal/family reasons. He had intended to remain involved with the Mk III project though.