Its got multiple edge dings and looking through that plastic other problems. It is not AU using British Grading standards.
I am in the United States not great britan yes it has edge dings i use u.s grading/pricing standards for u.s/world coins there grading/pricing is of course going to be different.
I'm fully aware you are in the US. In your OP you asked for opinions and said you were suspicious about it. I have given you the correct grade and upto date catalog price. £4 is $5.21
At a coin show, one of the dealers used to sell "foreign" silver for $0.60/g, so a thruppence would cost me ~$0.80
I am def. in the AU camp, the OP pictures are "pie-plate" sized and in hand would not be so prominent. This is right up my alley as I used to do the Krause cat. for many years. The big number values quoted above are for really exceptional examples on an issue that little care was given to striking these coins - soft strike with poor planchet prep., etc.