An online Beatles fan club for and about Beatle fans
Halloween night, Los Angeles, 1974 (MarkZapp)
In Liverpool, I kid you not, that would be called a twat hat. Coincidentally it also resembles the hats on the puppet Diddymen from Knotty Ash in the TV and stage shows of Liverpool comedian Ken Dodd, who played some of the same gigs as the lads.
I thought twat hats were the small flat caps JP&G were pictured wearing on the roof of the Bambi Kino in Hamburg (and to add insult to injury, the caps were pink).But the one George is wearing here does resemble the Diddymen.