Panasonic is, and always has been, Panasonic here in Ireland and in the UK.
They were unable to trademark "National" in many English and European language speaking markets which would also have the word "National" as it clashes with other brands or is too generic.
They used "National" in some European markets prior to 1980, but usually with a dual branding with Panasonic. I've certainly seen older Panasonic equipment which had a tiny logo containing the word National beside the Panasonic logo.
Technics is their brand for high-end audio, and is still around to some extent for DJ / studio equipment. Although, it has been dropped for high-end consumer marketing in Europe and the US.
It seems the National brand continues to be used in Japan in particular, but also in other parts of Asia.