Blood Concentrate products were most probably first used at Treloar's after March 1969. Linked evidence DHSC0100025_098 - Letter from S G Rainsford to Dr W dA Maycock - 18 Mar 1969 Chronology Information Date: 1 March 1969 Chapter/issue Treloars Key Person(s) Dr Seymour G Rainsford Sir William Maycock)