Sorry I can't help with any details except that there was the version like Geoff posted and also a farm version with shorter seat, big racks etc.
I also recall that tyres are near on impossible to find for them?
My best mate from school had one and I've got great memories of us two trying to ride it when it started up one day and was running in reverse!
I stalled it and spoiled the fun.
P.S. I'm sure I've got a Classic Motorcycle Mechanics article on them too. If you're interested, let me know and I'll email you a copy.