A few days later during an eBay trawl, this funny looking JP Edition popped up
Already known to many HHKB owners, a HASU controller board replaces the stock Topre one in your HHKB, allowing full programmability. There's even a Bluetooth controller if one wished to make their little beast wireless too. Ordering HASU controller boards can be done direct from the man himself. As it happened I managed to get the HASU and an additional set of ANSI caps from the same seller whom I purchased this keyboard from so I could make the keys resemble the newly programmed layout.
The GH HASU page had pretty much everything I needed to know on it. I fitted the controller, lubed the sliders and stabilisers with a bit of 205 G0 while I was there, got a little headache keeping the domes and springs in place while I was putting it all back together but overall, it was a fairly quick, painless experience.
Customising the layout was just as quick and easy
Using this board as I intended is great. However, the space bar's slight off centre positioning does throw me a little. I use my right thumb to hit space most of the time and it rests just below the gap between N and M. I've found that the space bar being a little shorter on the right sometimes pulls my right hand over to the left of the board a little too much and causes me to input a random string of alphas! This is why I made the key to the right space too.
So, all in all, if you like Topre, like the idea of a HHKB but don't wish to compromise your stubbornly held primary layer keyboard functionality, this may be the way to go. Yes, some of the legends still aren't right for a U.K. ISO layout, yes I can hear that I haven't seated the left control spring correctly and am going to have to dismantle it again after finishing typing this, and yes, HHKBs and their fixing still cost a bit, but this board ticks a lot of boxes for me at least; and it was one of the easiest keyboard projects I've embarked upon.