Late 18th/very early 19th century English set

One of my favourite sets in the cabinet, this set could be late 18th century, possibly very early 19th century due to the "urn" like turning.  I had believed this was possibly made from fruitwood (having compared to similar sets), but have been reliably informed that it is actually made from boxwood.

The set is larger than the 2.7" king height might otherwise imply  - after all, these sets don't have the king finials found on later Staunton or St George sets!  The knights are just over 2.1" in height, with 1.7" pawns.

An interesting feature is that one of its early owners signed their initials on the bottom of the white king...and dated it!  "J.B.R. 1830".  I do not believe this is the maker's signature, as it is not in keeping with the precision or artistry of the set.  I've been racking my brain trying to think why an owner would date their initials, though! Perhaps that was a thing, back in the day.

The knights are superbly carved - and bear more than a striking resemblance to signed/labelled Lund sets.  My hypothesis for this set therefore is that, if it is very early 19th century, it may possibly be by Thomas Lund himself (the later William Lund's father).  However, a couple of extremely knowledgeable and experienced collectors have commented that they believe the set is likely to be by Calvert!  I'm a happy boy whichever way you think this set falls!