Oh! Doing some quick research, the cross pommy has associations with the apple (that's one representation for the bulb on each side), which of course sends my brain straight back to Avalon:

Glastonbury = Avalon = The Isle of Apples
Glastonbury Tor -> St. Michael's Tower -> Cross pommy

:)

I love your ideas on that pairing, and the concept of the two hanging together is just beautiful.