1673 Halfcrown no stops

[Tony1982]

I have this nice Halfcrown dated 1673 with no stops to reverse. I can’t seem to find another anywhere in reference or previous sales. Does anyone know if it’s a know error ? 

[Tony1982]

[Paddy]

ESC mentions a variety with no stop after HIB, but not one with ne stops at all on the reverse.

 

[Citizen H]

I have found........., 

4th bust 

1673 KM# 438.1VICESIMO QVINTO

1673 KM# 438.2plume below bust

1673 KM# 438.3centre plume reverse

I've not found references to stops, hopefully others will chip in with more information ...  👍