This man enlisted as William CLARKE, so is "mis-filed" in the WW1 Service Records (WO 363). Sadly, the papers are badly damaged and thus difficult to make any sense of them ...

Michael McARDLE:
A Hair Dresser by trade, joined up on 15 March 1916, declaring age 25y 12 days. Started with the Lancs Fusiliers (27222), finished by serving in Italy with the Border Regt (30063).
Home address in 1916: 3 Gibside Terrace, BURNOPFIELD, Co Durham.

Married 10 June 1912 at BIRMOOR (Byermoor?) - bride's surname ends NDERSON. No separation allowance to be paid to his wife because she left him before he enlisted. (I cannot find this marriage)

Discharged February 1919; Intended address: PATRICK, ISLE OF MAN.

Worried letter from his sister (JACKSON? CLARKE? MARY?) in Feb 1919, having not heard from him.
Her address: 9 John Street, ANNFIELD PLAIN.

1922: Pension paid to McARDLE - EDMONDSLEY, Co Durham
1933: request for copy of discharge papers (from McARDLE) - home address SOUTH MOOR, Co Durham.

Hopefully, something here may ring a bell with someone!

Anc****y, CLA, pages 180032-180066