At 21, Horn relocated to London and took up work by playing in a band which involved re-recording top 20 songs for BBC radio due to the needle time restrictions then in place. This was followed by a one-year tenure with Ray McVay's big band, and earning as a session musician, producing jingles, records, and working with rock groups. His time with Ray McVay included performances at the world ballroom dancing championship and the television show "Come Dancing". At 24, Horn began a period of work in Leicester where his growing interest in recording studios led to his assistance in the construction of a studio in the city, while playing the bass at Bailey's club for seven nights for money. Upon completion of the studio, Horn produced songs for local artists, including a song for Leicester City F.C.