You'll be able to fit an early defender wheel, not the latest one. Or maybe a Santana wheel.
My Santana was retro-fittend with a Series III steering wheel so the santana wheel should fit your Series problem-free.
Check here and check the prices.
They are at the other side of the pond, in Iran, but the prices are worth looking at!
Alternatively, this other firm, located in the Netherlands, has also access to Santana and Morattab parts (the late Santana Series IV from the late '80s, early '90s is still produced in Iran).
Take a look here:
http://www.heystee-automotive.com/
Good luck