I did it by being incredibly stupid. I saw a similar set on an MGB and called Dayton Wire Wheels to find out how much.   In a weak moment, I ordered a set and one thing led to another. Then I found the MG logo on Abington Spares and ordered it for the spare tire. All I had to do was drill a hole in the spinner cap and fabricate a bracket. The adapter hubs bolted right on the old lugs, although I did have to buy smaller nuts. Then I made a quick trip to a local tire store that had a sale going.

I rationalize the cost by telling myself I will never sell the car, and I do love the look.
One last thing. After installing the wheels, the ride was much rougher, so I reduced the air pressure to 24 pounds. Problem solved