We're about to bring home our Norfolk Terrier puppy and just wanted some advice on grooming tools - what sort of brush(es) should we be getting? How often should we be grooming him?

A shedding knife is something you will need with a terrier coat. 

It is like a serrated edged blade bit like on a hacksaw, and it catches and helps pull the harsh dead hair.

A good steel comb with close tines one side and wider the other, often called a grey hound comb.

More combs than brushes for a terrier coat.

Hopefully, your breeder will supply information about coat care when you pick your puppy up. If they do not, make sure you ask If you do not intend on showing your new pup, then a 'Mars Coat King' can be invaluable for sorting the coat out of an adult dog. Details HERE. You would not need to use a Coat King more than once a week (at the most).