PG UNrelated BB King In London question

[wetcamelfood]

I know PG is only on "Caldonia" but I'm building up some content to the "BB King In London" album page in the discography and I noticed in the liner notes of my copy that there's someone billed as "The Mystery Shadow" as playing organ on "Blue Shadows" & "We Can't Agree" and in Google-ing it, some reports suggest it's Dr. John and others Steve Winwood but nothing concrete. Anyone here know? I can post this in the performance comments section but just thought I'd ask while working on it and would be more complete if we could come up with the name so let me know if you come across anything substantial on this and naturally I'll list you as a contributor of the page. Thanks for the feedback in advance (fingers crossed that there is some to come).

John