Andy,
I bought a ZX81 ULA replacement module from you.
Everyone else,
Also, I have the ULAs bearing 184 and 210. I ordered a ZX81 core board for the RC2014 Z80 platform last week. I expected that the board will arrive my mailbox next week or so. I might have to order a few BC547 and BC548 transistors and other electronic parts.
David Roper and Spencer Owen designed their own ZX81 Core Boards separately! Mr. Roper seems finished his own board and is ready to sell. Mr. Owen somewhat suspended his own board project. However, these two nice gentlemen are located in England(U.K.).