Firstly are they synomynous?
I have a data book , printed in 1933
Westinghouse "the all-metal way" metal rectifiers ,
how to build High Tension battery eliminators
and battery chargers.
A 300V , 60mA Westinghouse one in 1933 was about 3x3x5 inches,
no mention of Selenium, trade secret then ?.

The pic
http://home.graffiti.net/diverse:graffiti.net/Se_R.jpg
Shows on the right a disassemled one from a 1959 Dansette, one of
the two , 8 layer blocks is shown, removed, on end near the ruler (0.1 inch)
Single element rectifier
Siemens lazy S logo
Made in Germany
E 250c50
Kc 0.6e 11/16
1979 Siemens databook and E250C50 were still listed,
rating 200V, 20mA

The book page is from 1967 catalogue.

Would the English military have had access to these size
and sort of ratings, of the later rectifiers, in 1940s,
they could have been heatsinked


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/