bobby-dazzler 
noun British informal, dated
A person or thing considered remarkable or excellent.A lot of women are saving their real bobby-dazzlers for Ladies Day or later in the week, not least because the weather is supposed to be getting better....
- Actually it's just the one trick, but it's a bobby-dazzler.
Origin
Mid 19th century (originally northern English dialect): related to dazzle; the origin of the first element is unknown.