The axle is unique to the car, which is why some have had axles from Robins fitted, but shares no parts with anything BMC. It's a tough axle though, which is why a few builders of modified Bedford Rascals have given up on their stock units after the third or fourth broken diff and swapped to a Reliant one instead.
Having owned many minis and kittens, I can say hand on heart that a kitten will outhandle a mini, especially in the wet where the rearward weight bias works in its favour. Minis have plenty of mechanical grip, which is what they do best, but in terms of handling prowess and the ability to steer on the throttle, the kitten takes some beating which was the main reason how, in the 12 or so years I competed in the Scottish Autotrader Series in one, our team were never beaten by the minis, not once. The only cars which ever pipped us in the finals were the classic Lotus Elans and even they didn't manage it the following year as we all let some air out of our back tyres to minimise wheelspin on the sharp bends and steep climbs involved.
On a circuit, the Loti would have wiped the floor with our factory stock kittens though I did embarrass a few on local tracks in LTF, my red estate which had 60+bhp in place of its original 43 thanks to a properly balanced and blueprinted engine running a FRC and big valves with A-series cam followers. That car would pull up the gentle upward section of A82 along Loch Lomondside in the overtaking lane at well over the speed limit on 7,800 rpm in third and it made the most glorious howl from its exhaust as it did it. Many of the other modified Reliant engines failed because they were running far too cool, so suffered with snapped cranks and piston skirts that picked up on the liners below the water jacket, causing smoke and bad noises. I had the radiator properly blanked off so that all of the air came from the vents under the bumper, it ran a 92 degree thermostat and 50% MPG-base coolant with distilled water in the system. When the present owner of the car broke that engine by failing to notice that the oil pressure relief valve was leaking (he took my pressure gauge out as he felt he needed a clock in there...), it had covered about 130,000 miles since I'd last had it apart. Why on earth did I sell that one eh? Apart from the fact that it had a manual gearbox.
Funnily enough, when I ran LTF as a daily right up while work insisted that I could no longer transport students around in it, I did wash it occasionally though because the (Pimento Red, one of the worst affected colours) paint suffered from the usual osmosis-related spots, I never used any wax, let alone nasty damaging polish so it looked awful but went like a thing possessed. Of course the MK3 Golf that followed it into daily service was just as economical, almost as quick and declared safe for my fussy employers' purposes. I should have taken an alternative post on rather than selling the kitten.
