I owned a Viscount back before the death fork recall and I might suggest there is another alternative to searching out pressed in cartridge bearings and putting up with the non-taper BB spindle.
Take the frame to a good shop or framebuilder. Have the BB taped to Italian threading, now go buy an Italian thread BB and new crankset.
Hell you could even get some TA cranks that use the same pattern as the Lambert cranks and use the original chainrings.

Marty