The FSA seems to have 4 different WHSmith stores in the airport but I can only find one here. Some of the FSA listings may be duplicates but they have at least airside, landside and landside arrivals.
 https://ratings.food.gov.uk/authority-search-landing/760?business-name-search=smith&address-search=AB21+7DU&business_type=-1&hygiene_status=all