Never did find that bloke again, so made my own with bits I had lying around.
Modified Suzuki trail bike 21" front wheels, made frame and forks to drawings in the book 'Motor Bicycle Building' first published in 1906 and used a modified Sachs two stroke stationary engine with belt drive. Fuel tank is exhaust tube with pressed ends and seat, handlebars and other small bits from evilbay.
It is not a 'real' bike but it goes and can be ridden around. Took to a bike show in Coffs Harbour last year and a lady from the local club made me an offer ($$$) I couldn't refuse as she wanted to put in her collection, so it now lives in Coffs.
For anyone interested in how I built it look to
https://2fiftycc.com/index.php?threads/15-m-e-c.8351/#post-84554And why MEC? well Murdo Engineering Construction.