Bickerton Portable, 1971~1989:
Front wheel: ISO298 (14x1 3/8)
Rear wheel: ISO349mm (16x1 3/8)
Tires in the ISO298 size have become rare since the 1971 design date. The Bickerton Portable intelligentsia has begun rebuilding their front wheels in common ISO305.
Modern bikes with Bickerton badging have been manufactured by Tern for several years.
Thanks for the info about the early wheels. That's a really strange front size.
As I said in #5 above, "There have been other threads on here in 2024 regarding a newer Bickerton bifold on the Dahon pattern (not original Bickerton)." I thought he had a more recent Bickerton, like another thread last year. I guess he has an original one! One of my early bike books deep in storage, has a drawing of one hung up on a coat rack.