Chris Hogg wrote:
[...]
alphabet punches
(if that's the right term) so that I can print them semi-neatly. I
imagine they're the sort of thing that model engineers and other
metalworkers might use. Does anyone know of a supplier?

The best tool shop I've known is Sargent's of Reading. They may not
still be around, I'm afraid, and they don't seem to have a web
presence. But if they're there, they'll have an eye-popping selection
of tools (they even used to import fascinating, and expensive,
Japanese traditional woodworking tools). Yellow Pp in library.

Otherwise, I'd look at the ads in metalworking magazines.

(There used to be machines (e.g. on railway stations) rather like
modern Dymo systems but huge, that gave you an embossed aluminium
label for the princely sum of 1d, IIRC. Long gone, sadly)

The bribe for the impatient child! I still have a couple somewhere. I
don't understand why they aren't about any more. On stations I
suppose some clown would vandalise them on principle; though it would
be a neat thing for an ironmonger or DIY shed to have inside.
[...]

--
Mike.