Grech originally gained notice in the United Kingdom as the bass guitar player for the progressive rock group Family. He joined the band when it was a largely blues-based live act in Leicester known as the Farinas. He became their bassist in 1965, replacing Tim Kirchin. Family released their first single, "Scene Through The Eye of a Lens," in September 1967 on the Liberty label in the UK, which got the band signed to Reprise Records. The group's 1968 debut album, Music in a Doll's House, was an underground hit that highlighted the songwriting talents of Roger Chapman and John "Charlie" Whitney as well as Chapman's piercing voice, but Grech also stood out with his rhythmic, thundering bass work on songs such as "Old Songs New Songs" and "See Through Windows," along with his aptitude on cello and violin.