John & Mary's is a shop owned by married couple John and Mary O'Leary, who not-so-secretly dislike each other.

The shop is seen when Dougal and Ted are protesting at the local cinema and Ted asks Dougal to buy a pair of handcuffs as well as Ted wanting a box of firelighters in the aftermath of Mr. Benson's whistle being stolen.

Mary attempts to kill her husband by dunking his head in a bucket of water, which he passes off as her washing his hair, and he locks her in a giant wardrobe.  They also come to blows over a shotgun which goes off when Ted leaves the shop.