I study these buttons my own view is its Lincoln City volunteers the two main sites I use are
https://thisreilluminatedschoolofmars.wordpress.com/ which is excellent for volunteers and militia. My facebook page has hundreds of vol and militia buttons with lots of daily posts and observations you can find it if you type british volunteer and militia buttons into facebook. The early military button website does have lots of images of buttons but some of the info is not correct and sadly its not been updated in years so new buttons and thoughts have not been added.