The monitor that it was hooked up to earlier was a
Dell S2719DGF which is incredibly nice for emulation and stuff like this (simulation?) because of it's variable refresh rate and free sync meaning it happily shunts down to 50Hz.
All I know at this point is that it was fine yesterday and Monday (which was the first day I used it). I think I tried it with the SD Card that was in it - but I only recall that having an example that flashed the LEDs on the board? I may not have paid too much attention, I was pretty tired at the time.
This evening I made up a 15pin to 23pin adapter and I now have it hooked up to my Microvitec M1438S. Have to say it's a better picture than the A1200!!
If the Analog RGB output really is only intended for developers then I may need to pay careful attention to release notes whenever I update anything because I never had any intention of using HDMI. I've not seen a scaling mode that I am 100% happy with yet and unless I'm imagining it, things seem more stable when coming out of the RGB rather than going through the scaler but that could just be my imagination.