I just found it in the back of my crockery cabinet! Looks like it's stayed in amongst my possessions for the nearly 20 years since I got it, through several house moves and stints in storage. It's going back on my desk now.
I can't find any the same as this when searching for it online now, but this seems the closest [2].
I like the simple text design much more than the coloured keyboard layout [3]; much more in keeping with the vi ethos.