I keep saying I'm done with this font, but I couldn't resist one more tweak. I added one more LED to make 5 for segments C and F, as the gaps due to the longer length of those segments detracted. This required a constant current circuit for the LED chains so the brightness would be uniform. Sorry about the lack of contrast in the photo, the time is 18:32. I really need to think of tinted perspex windows for the display. Ok, here's another photo with the ambient light dimmed.

As a matter of interest, I had to use the long exposure feature of my phone as the camera can detect the LED multiplexing.

There were the usual teething problems: a mistake in the pinout for the TL431, a missing feedback capacitor, one dud high side transistor, several bad solder joints, but I got it working.

Unfortunately the half-height zero is irremediable. The only mitigation I could apply is to use the upper loop.