Uniselector clock of unknown origins

Mike is looking for info regarding an unusual timekeeping device he came across –

At present I have no documentation for this clock, and it has no markings other than the labels for the controls and external connections, such as “LPS OFF”, meaning lamps off, “RESET”, meaning set the time, etc. Internally it is evidently hand built, with a few of the parts being obviously hand made but most being telephone exchange components. The lamp array is cut from ebonite and the offcuts used as brackets. The standard of construction is extremely high, as good as that seen in high quality test equipment and high end consumer electronics of the period, which I reckon to be mid 1940s, perhaps a little later.

The two rows of lamps up top display the current time driven by a set of relays. The top row shows the hour while the bottom displays minutes and tens of minutes. The calendar section sounds particularly interesting, using all mechanical parts –

Every 12 hours a lever is pressed and this advances the day dial, e.g. A.M. Mon advances to P.M. Mon. There’s also a date dial and a month dial. The month dial has a cam to set the number of days in the month. February has 28 days on the cam, but every 4 years this is advanced to 29 by an extra lever pushed into place by an extra wheel that advances every 6 months and completes one revolution every 4 years. A nice touch!

If you have any clues to its origin be sure to leave a comment. More on its operation can be found on his site.