Complex sentence: By the late 80's/early 90's Andys Records was fast becoming a well known name on the UK high street and became the UK's largest independent music retailer in 1992, a title it retained for 10 years.
Split into simpler sentences: By the late 80s to early 90s, Andys Records was fast becoming a well-known name on the UK High Street. It became the UK's largest independent music retailer in 1992, a title it retained for 10 years.