Hello Aidan and apologies for not responding sooner but I've been having trouble with my broadband at home. I did look into your suggestion but if you look on the reverse the halved shields of England and Scotland show that the coin was struck for the post-Union UK, despite the fact that it is dated 1706. I have added a note to the reverse description on the listing - hope this helps.
Just because you can't see it ... doesn't mean it isn't there - Anon.