Mabel Greer's Toyshop morphed into YES with their first official gig as a band named "YES" on August 3, 1968 at East Mersea Youth Camp, Essex.
For about a month prior to the "YES" debut, Peter Banks left Mabel Greer's Toyshop and joined the then skinhead band Neat Change.
The first two photos above by Sylvia Pitcher of Neat Change in July 1968 in the park feature them in their "skinhead" mode. Then they go through a magical hair and clothing transformation to a more pop sensibility for the cover to their DECCA single "I Lied To Auntie May" / "Sandman" (July 1968). It's the exact same lineup pictured in all 3 Neat Change band photos above, although it is most likely that Peter Banks didn't play for the recording of the single.
Then after only being in Neat Change for a few weeks, Peter Banks was out. He comes back to the transforming Mabel Greer's Toyshop/YES.
Peter Banks was in the Neat Change lineup for two gigs, both at Marquee Club London in July 1968: July 6 and July 13.