Career
He later played non-league football for Nuneaton Borough and Northwich Victoria. Armstrong played for Huddersfield Town, and made four Fourth Division appearances in the 1976-1977 season. However he did not feature at all in the title winning 1979-1980 campaign, and was also absent throughout the 1980-1981 season, before signing with Fourth Division Portuguese Vale in February 1981.
Armstrong made 17 appearances for the "Valiants" at the end of the 1980-1981 campaign, and claimed goals against Hereford United and Peterborough United.
He featured 42 times in the 1981-1982 season, scoring goals against Hartlepool United and Lincoln City. However he and numerous other players fell out with manager John McGrath over player wages, and as a result Armstrong, Barry Siddall, Russell Bromage, and Geoff Hunter all remained on weekly contracts.
Armstrong hit two goals in 21 matches in the 1983-1984 season as Vale were relegated out of the Third Division, despite an upturn in form under new boss John Rudge. Armstrong began to be plagued by a nagging knee injury, which required a cartilage operation.
In April 2003, he lost his job as a prison warder at Wakefield Prison after he was jailed for 28 days for sending sexually explicit material to the husband of his former lover - an act which was in breach of a restraining order.
He also graffitied a motorway bridge as an insult to the husband of his former lover. with Portuguese Vale.