Recorded evidence of that incarnation of the Bluesbreakers is, predictably, skinny, limited to two sides of a single (Double Trouble/It Hurts Me Too) and a couple of instrumentals to use up the studio time). Curly and Rubber Duck, along with the two sides of the single, turn up on the expanded reissue of Crusade (reviewed here) while a fifth track, Fleetwood Mac, an instrumental which Green named after the rhythm section, remained unissued.
Green didn't outlast Fleetwood by all that much, and when he jumped ship hadn't intended to go into another band, but the pair hooked up, found guitarist Jeremy Spencer in a Birmingham blues band (recommendation from Blue Horizon records man Mike Vernon) and wanted McVie on bass. Naming the new outfit Fleetwood Mac was supposed to encourage him to switch allegiances, but when the time came to take the plunge Mayall seemed like a safer option and the band made its debut at Windsor Jazz and Blues Festival on 13 August 1967 with Bob Brunning on bass.
Mayall, however, was moving towards jazz and it was only a matter of a few weeks before McVie became Fleetwood Mac's permanent bass player.
The quartet cut their first album, Fleetwood Mac in November and December 1967 and it came out on Vernon's Blue Horizon the following February. Did rather well for a no-frills blues album, too, reaching #4 in the album charts despite the absence of anything resembling a hit single.
Back in the studio in April they had a second album (Mr Wonderful) out in August, an enhanced affair with a horn section, one-man-blues-band Duster Bennett on harmonica and Chicken Shack's Christine Perfect on piano. We're still talking an all-blues affair, but the changes were seeping in.
There were a couple of singles (Black Magic Woman, later Santana's signature tune, and Need Your Love So Bad and, more significantly, a third guitarist in the form of eighteen years old Londoner Danny Kirwan, who Green had found in a South London trio called Boilerhouse. Green liked their style and offered them a tour opening for his band, but the rhythm section didn't want to turn professional. Ads in Melody Maker and auditions at the Nag's Head in Battersea (venue for Mike Vernon's Blue Horizon Club) failed to deliver a new rhythm section, so Green offered young Danny the gig as the third guitarist in the Mac.