Your mention of the Chatham Division made me think he was in the Royal Marines, and sure enough his record of service is on FindMyPast.
https://www.findmypast.co.uk/transcript?id=GBM/ADM159/35483/1Outline details are:
Born 12 June 1897 at Halling, Rochester, Kent
Enlisted at Chatham 26 Jan 1915 aged 17 yrs 7 months and 15 days. Formerly a farm labourer, height 5'5", eyes grey, fresh complexion and brown hair. Service number 19706
His was assigned to the Chatham Division Royal Marines Light Infantry andf held the rank of Marine (Private) for all of his service. He was discharged at Chatham 11 June 1927. Unfortunately the name of the ship he was on between 14 Oct 1922 and 1 Jun 1927 is obscure (picture below).
His next of kin was initially his father J Hawkes of 4 Burton Place Upper Halling, then after his marriage on 27 Oct 1923 at St Michael's parish church Maidstone, it was his wife Clara Annie, 19 Warwick Place, Tonbridge Rd, Maidstone.
He served with the Middle East Force in the Dardenelles 22 Oct 1915 - 19 May 1916 and was wounded on 11 Dec 1915