Cant think of a title for this post. The failed SMPSU has been refunded. No actual communication from the seller (apparently the sellers proper trading name is 'LeadCoo Ltd'), but a very prompt refund with no hassle.
Sadly, the cost of these supplies has over doubled! So ive ordered a replacement from a UK based (allegedly) seller. Ive also had to order more nut rivets for the mounting, and replacement fuses, as im all but out of them!
The IR remote control tester works nicely, but rather than continue with that now and try to fathom out a way to include 6v worth of battery and a 5v regulator into a 1inch mint tin, ive decided to instead power it from USB! To this end, a bit of shopping around on ebay found me ten micro-USB 'break-out' boards for a quid. These simply give you four PCB through holes on a 0.1" pitch, intended of course for SIL headers. But will allow simple circuits like this to be build dead-bug on the board.
Ive also finally got the box for the Theremin coming. Again that has proved to be far from cheap! But with any luck that will be another project complete and finished with soon.