There is no asterisk by Samuel Sinclair’s name on The Roll of Honour so presumably he survived the war.
There is an index card for him in The Flintshire Roll of Honour at The County Record Office in Hawarden. (Card Queensferry L111) It confirms his regimental details as above and says his period of service was 4 and 1/2 years. The card was signed by Samuel Sinclair himself on the 25th September 1919. On the reverse he had written that he had joined the Royal Welsh Fusiliers, 8th Bttn and that he had seen service abroad with them. He had been Invalided home then transferred to the ?? North Staffs regiment.
He was honoured by the people of Queensferry by having his name put on the “Roll of Honour”.