Completed! Checked around with the meter for shorts etc., then powered up from mains voltage. No smoke.
It's so handy having a 3D printer, this little box holds the USB interface attached to the rear plate, only took a couple of minutes in SketchUp and 15mins to print. A wole lot quicker than fabricating even a simple bracket by hand.
I was hoping to get (up to) 48v out of the thing when fed ~52V input but no - maximum stable is 42V. It will go up to an indicated 46V but as you can see from the PC readout the output is unstable.
At 42V it's quite accurate as indicated by the Brymen 869s:
Set to 48V I only get and unstable 46V (sawtooth output):
These are figures with the output unloaded.. Next I will do some load tests using my Maynuo electronic load, can't get near the theoretical maximum with that as 150w is the max, but I can check temperatures at that.