As mentioned upthread, some of the Rimlocks received American registrations and designations in 1955. Included were the following, all with 1955 October 10 dates:
EF41 as 6CJ5
ECH42 as 6CU7
EBC41 as 6CV7
EAF42 as 6CT7
EK41 as 6CK5
UF41 as 12AC5
On its face, that is puzzling, as by late 1955, Philips had completed its noval radio series, late issues being the EF89 and EBF89, and had released in Europe the EBC81, previously held back from that market. So by then the Rimlocks were no longer “front line” valves.
One possible explanation is that this was done to provide designations that better suited the Australian market, where although Rimlocks were apparently never manufactured nor used in Australian-made equipment, nonetheless they were imported to provide spares for imported equipment that was fitted with Rimlock valves. Here is a 1954 Australian advertisement for Eddystone receivers that does mention the (Rimlock) valves used therein.
I don’t recall whether the Rimlocks sold in NZ in the 1960s showed both the original and the American designations. Probably so, as quite a few valves did have double designations, and NZ was essentially bilingual, as it were, when it came to valve designations.. But when Rimlocks were used as original equipment in NZ, as in the early versions of the famous Bell Colt radio receiver, it was with their original designations.
Cheers,