Finally took some pictures of the thing...
here, the mirror finish is clear, and the dot along the bottom is showing about 20 seconds into the min.
here we have the back view, Arduino nano in the middle, RTC on the right and a block of plasticard on the left (so it sits flat on the wall)
the LDR kinda pokes up above the parapet and is held in place with a globule of hot-melt glue.
all of the wires... these are to try to distribute power evenly as the traces on the board (+5V) don't seem to work too well.
it may be hard to see, but the LEDs have got blobs of thick black paint (car touch-up paint) on them to help prevent light leakage in a dark bedroom