Vintage could be older brass/ copper letter box front stunning!! This incredibly well aged ( patina) letter box door opening is probably 100 years old ! Difficult to age but the verdigris and patina would have taken year's and year's to build up you can't fake age like this !!? Very heavy well made item some age related wear 26 cm wide 8 cm tall 2 cm depth 
House letter boxes, the slots or receptacles for mail at homes, have a history dating back to the mid-19th century in the UK. Before this, postmen would typically have to knock on doors to deliver mail. The Royal Mail encouraged households to install letterboxes starting around 1849. 
Here's a more detailed look at the evolution:
Early 1800s:
Before the widespread adoption of letterboxes, mail was often delivered by hand, and the postman would have to knock on doors to collect or deliver mail. 
Mid-1800s:
The Royal Mail began promoting the installation of letterboxes in homes, starting in the mid-1840s. 
Early Styles:
Early letterboxes were often simple holes or flaps in the door, sometimes with a simple spring mechanism to keep the flap closed. 
Evolution of Designs:
Over time, letterbox designs evolved to incorporate features like flaps, spring mechanisms, and various materials like wood, iron, and later cast iron. 
Mandatory Requirement:
By the 1920s, letterboxes in homes became a more common sight, and in 1923, the Royal Mail made it mandatory for all properties to have a letterbox.