Obverse:

ELIZAB D G ANG FR ET HIB REGI. Crowned bust 6B l, beaded inner circle.

Reverse:

POSVI DEV ADIVTOREM MEV. Square topped shield over long cross fourchee dividing the legend. 

Fine or just so, the overmark very rare, even more so for both sides.

Ex C. Comber Collection 

Reportedly Ex R. Shuttlewood Collection (not in sale ).