Thanks Joe. It's an easy chop I suppose as the 'glass' comes in one piece, I put Tamiya masking tape around the bottom and cut the top off with a craft saw. The roof took the time, cutting it into four, adding plastic sheet inside to cover a larger area and filling and sanding down the top of it. And having to cut the wiper blades shorter so as not to wipe the roof!
This was my inspiration, having been around when this photo was taken in the 60's of Stirling Moss (far left) and the Minisprint being unveiled and later taking it to the track.