Most students of the Hermetic Kabbalah will know (sometimes obsessively) about the Golden Dawn and various splinter offshoots that carried that tradition into the period between the two world wars. WW2 was hugely destructive to esoteric traditions in Europe. The history of the generation that began again after WW2 is in many cases still anecdotal and survives in the memories of a second and third generation of students.
I would like to point out research by Cherry Gilchrist and Rod Thorne into a loose association of students of the esoteric and Kabbalah that nucleated in central London in the late 50s and early 60s. In particular, this useful article by Cherry Gilchrist into the origins of The Extended Tree: