Many of John's recordings in this studio have surfaced on unauthorized releases (some on Anthology 2). Most notably, early "Strawberry Fields Forever" home demos. Some of the incidental music heard in the Magical Myster Tour film was probaly recorded here, too.
John had his Gibson J-160E guitar painted in June 1967 which would place these photos sometime after that. There is minimal Lennon output from this era so it would be difficult to speculate what song(s) he might be working on.