[Maarten]

The double M on the plate is something I've never seen before and may indicate another factory than a single M (or it was a simple error - by any chance, is the first M printed and the second M stamped?) but it is at this point extremely likely the set was both designed and manufactured in Great Britain.

Interestingly, the type plate itself was designed in the Netherlands as A1 872 is a Dutch issued part number missing the last 2 or 3 digits (it would be nice if you could decipher them).

Edit: I only see now, that you linked some (very nice and sharp) pictures. The second M is indeed stamped. The stamping machine was probably adjusted to non-pre printed type plates so for practical intents and purposes I would consider this a single M. Also the last (5 even) characters of the type plate's article code A1 872 23.0/A are visible, quite interesting for my archives. The voltage not being stamped wasn't a mistake but rather usual practice for sets with adjustable mains voltage.