It's an original one, 1602-05 although I got that one with another console, a modded 1601 while I was in the UK. I don't remember having freezing issues with other games on my original console; I'll try again with the original adapter.
It's a Build-It-Yourself kit indeed, from
Monster Joysticks, a UK business which started with Raspberry Pi kits, then sticks for retro consoles and computers.
I discovered them thanks to a nice Youtube retro computing channel,
RMC, which they sponsor.
I also built 2 Master System ones. They offer artwork covers for those, so you can design your own decoration, as they work with various machines. The SMS has virtually no arcade stick properly speaking, so it's awesome to be able to build your own.
