Sedgewick joins as editorial director, while Bev Douglas comes on broad as art director and Christina Ryder as managing editor. Sedgewick was creative director and board director of Citrus Publishing for three years before she helped to set up NatMag Contract in 2002.
She has also worked at The Observer, Sunday Telegraph and Harpers & Queen, as well as customer publishing houses Forward and John Brown.
Douglas launched Emporium magazine for BAA and New Home magazine for Berkley Homes. She has also worked for The Guardian, The Observer and Dennis Publishing. Ryder has also worked on BAA Emporium and Berkley Homes.
Of the appointments, Peter Dean, creative director of Square One, said: "Their breadth of experience perfectly complements ours and means that we can offer new and exciting clients an unrivalled package of creative solutions."
NatMags closed its customer publishing division in February, blaming insufficient margins.
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