If your WW1 ancestor was an officer, then they are going to be listed in The Gazette, service personnel commissioned, promoted, posted or awarded a medal or other honour are “gazetted” (you can also be gazetted if you are bankrupted!).
The Gazette has been recording national and international events since November 1665, inaugurated as The Oxford Gazette. It is a prime resource which can be used to draw out a soldier’s career. In times of conflict such as World War 1 it recorded despatches from the front, honours and awards for gallantry or meritorious service – as well as officer commissions, appointments and promotions, and casualties.
The Gazette website notes:
The Gazette is formally the combination of three publications: The London Gazette, The Belfast Gazette and The Edinburgh Gazette. The Gazettes are official journals of record.
As a publication, The Gazette consists largely of statutory notices. This means that there is some legal requirement for the notice placer to advertise an event or proposal in The Gazette.
There are over 450 different types of notice that are advertised in The Gazette, including:
- 242 notice types required by law to be published in The Gazette
- 82 notice types required by law to be published in The Gazette, as well as somewhere else (for example, a newspaper)
- 54 notice types required by law to be published, but the law doesn’t specify where
- 36 notice types that may be published in The Gazette
- 41 notice types that are optional publication, so are not required by law to be published
The Gazette website provides information on these different types of notice and the legislation that governs their publication here.
The legal power to print and publish The Gazette is a prerogative power conferred on the Queen’s Printer by letters patent. Letters patent are a type of legal instrument in the form of a published written order, in this case issued by the monarch. The Queen’s Printer and the Controller of HMSO have historically been viewed as one and the same person, and it can be inferred that the functions of the Queen’s Printer are to be carried out by HMSO operating from within The National Archives, under the direction of the Controller and Keeper (who is the chief executive of The National Archives). The National Archives (HMSO) manages the publication of all three of the individual Gazette titles (London, Belfast and Edinburgh) for the Queen’s Printer, under a concessionary contract.
Just as an example, a random search (not quite I searched for Captain Colclough) in a matter of minutes I found…
‘Admiralty, 23rd September 1915.
Royal Naval Reserve.
Lieutenant Robert John Williams to be – Lieutenant Commander. Dated 10th. August, 1915.
Lieutenant Frank Colclough Ree to be Lieutenant Commander. Dated 27th August, 1915.
Sub-Lieutenant Charles Jancey Davis to be – Lieutenant. Dated 10th June, 1915.’ 
‘Admiralty, 28th December 1915.
Royal Naval Reserve.
In accordance with the Regulations for the Royal Naval Reserve, Lieutenant-Commander Frank Colclough Ree has been placed on the Retired List. Dated 27th December 1915.
To be temporary Engineer Sub-Lieutenant— Henry Charles Handcock. Dated 22nd December 1915.
Temporary Sub-Lieutenant David James to be temporary Lieutenant. Dated 28th December 1915’.
Six names found already, and in a Colclough biography Frank Colclough Ree was in the Royal Naval Reserve and not long before he was retired, he was promoted. Food for thought?
A few other ways to find an officer might be in The National Archives which has manuscript army lists 1702-1752, service records 1764-1913, pension records – widow’s pensions, half-pay pensions, etc. and selected birth, marriage and death certificates for British Army Officers 1755-1908.
 The Gazette. About The Gazette. https://www.thegazette.co.uk/all-notices/content/100507 : accessed 21 February 2021
 The Gazzette. The London Gazette Publication date:28 September 1915Issue:29310Page:9549 https://www.thegazette.co.uk/London/issue/29310/page/9549/data.htm : accessed 21 February 2021.
 The Gazette. The London Gazette Publication date:31 December 1915Issue:29421Page:13024 https://www.thegazette.co.uk/London/issue/29421/page/13024/data.htm : accessed 21 February 2021.
 National Archives (Great Britain) Research guides: A-Z index.
accessed 21 February 2021.