A series of regular blog posts displaying images from “British Cavalry Uniforms of the 19th Century”; a set of trade cards issued by Badshah Tea Co. of London in 1963.
#22: The 4th Queens Own Dragoons
“The regiment was raised in 1685 and numbered the 4th in 1742. In 1788 it became the 4th Queen’s Own Dragoons and was then converted to Hussars in 1861. The uniform of the regiment as it was about 1808 is shown here.”

Sites of interest about the 4th Queen’s Own Dragoons:
The International Churchill society have this detailed history on Winston Churchill and his time in the 4th Queen’s Own Hussars.
The Wikipedia page on the 4th Queen’s Own Hussars.
A good summary of the regiment’s history here on “The British Empire” website.
The museum of the Queen’s Royal Irish Hussars in Eastbourne, East Sussex.