Bought this spoon today. Only show the hallmarks here.
The maker is John Lambe, 1789, in London.
The hallmarks are identical to those found in 1809. But from the maker we can deduce that it is produced in 1789.
The hallmark is definitely 1789 and not 1809 as by 1809 the orientation of the marks on larger spoons was vertical rather than horizontal. The shape of the punch points towards John Lambe.
A spoon of this size is useful nowadays as a table spoon but I understand that originally it would have been used for soup.