To be honest I bought five (5) CPLD chips from a Far East supplier and only 2 are fine. Anyway, good luck with your board.
@superfo designed an interface to the Issue 1. The interface is a combination of the Kempston type joystick port and the IF2 cartridge slot. It works with any ZX Spectrum and is compact and very handy. See below.
And the last but not least, below is a teaser about the Issue 2 board. This PCB is still hot and arrived to me a few days ago.