Yeh, spot-on Mark (of course).
Apparently, Mitch remembers he & RL came about 5th in oZ trials titles on that sidecar version Tossa mentions. It was just a chair bolted to Mitch's 250 enduro w an extra heavy flywheel.
Just found an old ad for Sprite Developments 405 Trials Rustler. Specs 84x72, 30hp @ 5500, 32mm Amal, 4sp, 51" w'base, 30" seat ht, 11" ground clearence, 198lb. (Husky-clone motor, but w side port barrel & single downtube frame) But Alron never brought them in as far as I know.
Article posted above by Alison which she sent me a copy in the mail, says 1st Sprite frames in 64 were a strengthened copy/version of Cotton Cougar frame, w Norton Roadholder forks, till he made his own swingarm front end when norton supply ran out. Was the cougar frame any/much diff to the cobra frame?
Alron M/Cs were variously reported to have sold Suzuki, Yamaha, Triumph, BMW, Rickman & even Motobecane (tho the latter may not have happened as it was the time of the french nuclear tests in the Pacififc & there was a union ban on Fr imports.) Mitch said they sold a lot of road Rickmans & a few 125 Zundap-engined enduros.
I've tracked down Brian Clarkson. He thinks he still may have his records from the shop at Granville. If he has (& can find it) he maybe able to check how many Alrons he sold, but he lost a lot of paperwork in a flood a few months ago, so we maybe too late. He's fairly sure he sold "3 or 4 x400s" ("People liked their grunty power") & "2 x250s" - MXs). He says the 400's g'box wasn't any/much worse than the Husky's (which he rode for many yrs prior to the Alron) as far as he can recall but rings/pistons didn't last as long. Someone stole his 400 from a friends place at Bathurst. He sold lots of Rickmans for them too - mostly road ones but "quite a few VR-engine MXs" too. He knows nothing of the supposed Rickman 250 Enduro RL supposed built & "sold about 30" of.