https://www.thegazette.co.uk/ the UK`s official public record is a resource I have not come across before.
This is useful for background information on People, Places and Events rather than for identifying a find.
Finding a Napoleonic era button in January, which had all the information on it, Wherwell Loyal Volunteers, Firmin and Westall, 153 STRAND.
Could not find any further information on this unit. Have been corresponding with the local History group, as one of their members had also found a button , a decade earlier.
The Royal Hants Regimental Museum, were very helpful but their info was very general, rather than specific, although they did point me in the direction of the Hampshire Records Office, who seemed to have specific info. The HRO were contacted and managed to provide 5 hits from a book, THE History of the First Volunteer Battalion, Hampshire Regiment, 3 of the hits were viewable, one of which gave the names of the 5 Officers and their rank. This was the first recorded mention of the Militia we had found. The book was published in 1905. The publisher Simpkin, triggered a memory. 35 years ago I worked in a pub and when it closed down, they said I could have a momento. Aligning the walls , were prints by Simpkin ( a different one ) of various Regiments, I actually had 3, one being the Royal Hants. Luckily I still have some brain cells and can remember something about the Gazette, which is the only time I have come across it.
Typing into " archive " on the Gazette website, garnished a few hits and the info for the book had been lifted from there a Century ago. Managed to enhance my info a little bit more, including promotions and resignations of some of the already known officers, plus a couple of new individuals. These names tied in with village records of the Historical group. The earliest mention of the Volunteers from the Gazette appears to be 1803 and the latest at the moment 1808. This has been a significant breakthrough and also important to the village in restoring a lost piece of their village History. Also from this info and the lack of archives from Firmins, who did reply to an email, I will date the button as 1803 possibly 1804.
Hope the Gazette may be of help to you in the future.
Cheers,

Dave.