British Coins "Petition" Crown + Museum Quality Coins -The Art of Coins
'Petitition' Crown is the Worlds Most Prestigious and Valuable Silver Coin
The engraving is that of Simon ?

    

Proof 1664                                                 Regular 1664
[Thomas Simons work]                                                                    

Extra differences between the above specimans

PROOF

The hair has the natural flowing style of Simon.
The bust is of Rottier with magic touch of  Simon around the eyes, nose & neck 
giving greater detail and shading. The effect of natural depth in the neck.
The tie ribbons are nearly straight
The lower curls at the bottom of the bust are Simons style.
The feilds are a proof field.[as the "Petition" Crown]