Yolanda Bruce has provided further details about him:

m. 1912 to Ann Wallace Munro. He served with the Gordon Highlanders in WW 1. Although he died on 6 June 1919, he is listed on the Commonwealth War Graves Commission site as a "Commonwealth War Dead". Presumably he died from injuries suffered during the war. The CWGC records that he is buried at Allenvale Cemetery in Aberdeen. The Scotlandspeople index of marriages has a very curious listing for Samuel’s marriage in 1912. It has his marriage indexed under the War and Service Returns (which unfortunately means No Image is available on-line). However under the same reference number (056/AF 0053), it lists his spouse under 4 completely different names; Flora McCorquodale, Isabella McLean, Ann Wallace Munro and Elizabeth Welsh). I have recorded her as Ann Wallace Munro as that is the name shown on the CWGC site.

Elaine McGary has since provided the following update:

I can confirm that Samuel Watson Mutch married Ann Wallace Munro on 4 March 1912 in Calcutta, India, while he was serving with the 2nd Btn.of The Gordon Highlanders at Cawnpore, India. The marriage took place in St. Andrew's Church in Calcutta. In the marriage record, Samuel gives his age as 31, his profession as a Soldier residing in Cawnpore. He gives his father's name as James Jackson, a farmer. Ann Munro gives her age as 29, residing in Calcutta, father Alexander Munro, a policeman. The witnesses at the marriage were James Ritchie and Alex Tosh Durno. Yolanda (Bruce) has given the correct reference for Samuel's marriage (056/AF 0053), however I can clear up the confusion of the other three spouse names on the record listing she found. The record contains the marriage returns for three other military marriages, the other spouse names (Flora McCorquodale, Isabella McLean, Elizabeth Welsh) are the spouses of these other marriages. Samuel's Army records show that he and Ann had a son, Colin Munro Mutch, born 16 December 1912 in Cawnpore, baptised 20 January 1913 in Cawnpore. Samuel enlisted in the Gordon Highlanders on 3 August 1900 and served continuously overseas for 12 years, in India and Egypt. In March 1914 he returned to the UK for a Rifle course, during which he became ill. Due to his ill health (diabetes), he was invalided out of the army in November 1914 as no longer physically fit for service, and was awarded a military pension.