Rover have tried out 2-strokes here and there, but never in great amounts, and back in there earliest times the seemed to have been a little more interested in looking appealing (Personally i think the late 70's switch to red was not a good move)
I have seen early (and I mean quite early) Rovers running Simplex 2-stroke engines, and then a little later they were running the Villiers 2-strokes (Such as the 7F) but at the point that Briggs became a viable motor in Australia, they moved the whole lot across rapidly, and after that the only 2-stroke I know of was the early 90's 2-stroke XL, powered by Suzuki.
They also seem to be slow to adapt to me, going back pre-80's, they Held on to the old rotating height adjuster way to long (Victa abandoned that thing by 1960, but Rover kept there version into the Mid-60's to my knowledge) And by 1972 Victa had a self propelled that ran an internal clutch gearbox, internally driven wheels, and a covered and discreet belt that made it very reliable and safe, while even upto the late 70's Rover still had a belt running to a rod at the back, that lifted on and off the rear wheels, very exposed, primitive and dangerous.
Really, the only thing Rover had going for them was the 4-stroke market, due to their uptake of Briggs, for the 4-stroke customers, rover had better range and pricing, while Victa remained for a long time the brand for us 2-stroke Junkies!
Thanks to Victa's stronghold on the Australian Market for so long, then Rovers grasp of the four strokes, it was Very hard for others to come in, especially those making there own engines, Turner did alright in the 60's with there bases and Kirby motors, but there sales were mostly based on providing wheels for other companies engines.
Many brands experimented with various engine manufacturers, while turner was mostly Kirby, Scotty has used Villiers, Briggs, J.A.P and there own engines in my experience, Rover has used Kirby, Tecumseh, Villiers, Suzuki, Briggs and Simplex, Boundy Industries did there own thing, with there crank case magneto, but never really made it big, and now are as scarce as hen's teeth.
Heck, My rotoscythe is self propelled, all internally, with a rear catcher, and BUX 2-stroke engine, all in the late 50's, and before Victa, Rover or most others had popped a catcher up the back or even created crude self propelled models, however it is massive, heavy, and cant be folded!
All in all, I think Victa made their ground by being simple, light and robust, they stayed progressuve, without becoming over complicated or cumbersome, and remained user friendly, hence why so many of there machines are still running after 30+ years with minimal maintenance, they kept it simple and reliable when the competition was all over the shop, and thats how they got the name up, after that they had the market, until the 4-stroke became more accessible, and reliable, and recently much more popular.
Not to mention, the early 4-strokes in Australia did not really make the market happy, Kirby engines just didn't keep up with the reliability, and the early alternatives were far and few between, and many still quite crude.
Scotty seems to have gotten more rotary's out than some, the Scotty powered ones are rare, the Villiers ones, also rare, the JAP ones even rarer, but the Briggs powered Scotty's that came a little later are not so rare, that seems to be when they actually got a few out the door.
