"A PORKY PRIME CUT" is the signature of British record cutting engineer George "Porky" Peckham.
Originally a guitarist & singer with 1960s group The Fourmost, and managed by Brian Epstein, he left & joined Apple in 1968. Peckham's signature appeared on Beatles records from that point. (Link?)
Peckham worked for Chas Chandler (ex Animals bass player & Jimi Hendrix manager) at IBC Studios in Portland Place through the 1970s cutting a lot of the punk records of the time, this is the period when the second batch of C.I.D. was pressed.
His signature also appears on Stranglehold, Tomorrows GirlsAnother Kind of Blues after which Gem switched to TAPE 1 for future pressings, although Porky makes a come back in 1986 with Dojo's Subs Standards and with LINK Records 1990 re-press of Endangered Species.