Nice piece! Where is everyone getting these great maritime weapons! A little piracy and it would be mine!

There is a sword in Annis' "Naval Swords" with a similar marking from the dockyard as noted, same period/dating with the block letters GR and crown. Hilt classic for the period, spiralled iron as found on so many of these cutlasses. The marking is intriguing, but I don't recognize it. Not that long ago, I saw a similar marking of a ship with initials, but NOT to confuse the matter, that was on a ship's lathing axe (not a boarding axe) from the U.S. circa 1850.
On most cutlass that went to sea, if they were Naval, they'd have a specific marking to such. Private purchase might have a partial marking, like a crown or maker mark. The point is, I don't think this piece was either of these, but very possibly made for the security that protected the waterfront/ships/cargo areas at the docks. As naval police, they would have carried something similar to their collegues, i would think. This would explain the unique marking of the ship. Just a guess, though.