This is the title of a recent television show about organized crime. The name itself is apparently old Birminghamese for “fancy lads wearing flat caps”, and was an appellation applied to a street gang that fit this description. It later came to to be a generic term used to refer to Birmingham street gangs generally.

Yes, in this context “blinder” is a noun that means “well-dressed gentleman”. Be aware though that this is a regional Britishism, and likely would not be used or understood outside certain specific areas of England.