Minis, with their A sequence integrated tranny / oil pan arrangement, are sometimes difficult to bolt together with common engine stand. Among the best Mini engine builders use engine stand plates of their own making. It's not a frequent part and these can't found easily. There is just about the guy in the U.K. on ebay selling them and his are nice, BTW.
But with a welder buddy, an online source for material or a local steel yard you may make your own for as much as $25. It's not completely fair to assume 'welder buddies' are falling out of trees. But you must persevere. If are usually crazy enough to carry out mechanical work a good obsolete British engine then you must know other crazy citizens. Crazy-land is the arena of good welders. All that is requires is a verbal challenge, like 'This bracket I'm working on looks like it's hard to weld together straight'. Generally sets the hook with a welder buddy.
Here's your short shopping list:
The block castings we can access are plenty strong and easy to begin. They are; the oil filter mounting plate surface and the generator / alternator mounting bracket eyes. As this area is but not on the ports side of the motor, there is less stuff you can't get to. Here's the trick; 2 mounts are not in the same plane. The oil filter mount surface is a few degrees out of this generator mount depends upon would be finished the project much sooner.
That's why I cut, drilled and fit my backing plates in two pieces. Bolt them up and if you did a good job the edges basically touch. Then tack weld associated with them. Take great care here since you are introducing fire to an area with gas, oil, solvents; as much as possible good. hopefully without combustion. Remove the tacked parts, weld them up and re-fit. When you're happy with your plate, it's period for weld on the round pipe, that is definitely notched with a hacksaw to better fit the two uneven surfaces.
The last part is to drill a hole in the round pipe to locate your engine by dropping a dowel or bolt the actual hole. Over-rotate you can just a bit, since it's weighted more on one end and you want it to wind up square. Other holes can be added so it can be located upside down, etc.
Last detail, order up some Mini Mania Mowog green engine paint inside your stand for abilities pro look, even perhaps a Speedwell or Downton sticker also.