"peter blue" mystery

[lazy poker]

"in the summertime when the forum is dry . . ." sometimes odd questions come along and want to be answered - such as this: has anybody got an idea as to when the picture of "peter blue" on duster bennett's "bright lights" album might have been taken?

i noticed that all of the musical participants (apart from stella sutton, that is) display a similarly cropped haircut on that album's cover back (maybe to tie in with duster's own hairstyle?). the album was recorded and released in 1969 at a time when fleetwood mac had just left blue horizon records and when peter was wearing considerably long hair. this photo, though, reminds me more than anything else of peter's time with peter b's looners ca. 1966. even with john mayall he had longer hair.

can anybody out there solve this mystery?