Unknown British buttons. Pitt & Co, London.
 

I have no idea what these are but they are fairly distinctive.

Postilion to King George Vth, assuming they are small sized

Thank you for the information and yes, they are small sized.

Still in use with the Queen on her Ascot coachmen.

When they remake new livery jackets for them, the buttons get recycled and replated to go onto the new ones.

Thank you for your message and your wonderful picture of KC buttons being used in the 21st century.

I have an identical button sold as Falkland Islands Customs, so possibly used by more than one organisation authorised to wear the crown.

Graham

The postilion button has rays and is half ball.
The Falkland Islands Customs' button has a rope grommet.
Please find scans of both buttons attached.

Thank you, I have both which were sold as FI Customs, it looks like the seller wrongly attributed the one in question.

Graham