He started the 1971–72 season by leading Halifax to a 2–1 Watney Cup victory over a full-strength Manchester United side, which included George Best, Denis Law and Bobby Charlton.
At Watford, injuries, boardroom unrest, and a shortage of luck and money conspired to produce two terrible winters consisting of one humiliation and very nearly a second.
He later moved to Iceland, where he managed one of the country's leading clubs; Íþróttabandalag Akraness (ÍA)[7][8] In 1978, he left Akranes and returned to Halifax.
Kirby inspired the team to another famous victory over Mancunian rivals; this time, it was the turn of Malcolm Allison's Manchester City, who fell to a single Paul Hendrie goal in an FA Cup 3rd round tie in January 1980.
His second spell with the Yorkshire club ended in June 1981 after a string of poor results saw his team finish second bottom of the old 4th division.