Brother-in-law of my great grandfather, Denis McMullen, joined the British Army in Chicago/Canada in February 1918. Deserted May 1918 from Stonar Camp near Richborough, Kent. There was a story in the family about someone being "chased" when they came to see relations in Liverpool because they were AWOL from the army. It must have been him. There's a 47 page British Army record for him on Ancestry that I recently discovered. The army wrote to his mother in County Antrim asking about his whereabouts. He was back in Chicago in September 1918 as he was recorded on the US Draft Registration.