Correction: I don't know how numerous was in fact Humber LRC III - at least one existed after the war, but it might have been not numerous car.
I have no information on White Scout Car (unit 400) in Czechoslovak Army, and it isn't mentioned on the quoted page
http://forum.valka.cz/viewtopic.php/t/36231
On the other hand, quite popular in the Czechoslovak army until mid-50s was Humber Scout Car. They also used some number of M5A1 halftracks and Bren carriers.
Regards
Michal