The three men entered the store at around 12pm on Wednesday 2 February and used payment cards to purchase cigarettes, games, and other items worth around £600 in total.
The goods were paid in separate transactions using separate cards with no chip and pin security, meaning the suspects had to sign for their purchases.
All three are described as white with non-British accents.
The first was around 5ft 7in, of thin build with short dark hair.
He was wearing dark coloured trousers and jacket with a red shirt underneath. The second was around 5ft 9in of medium build and was wearing dark coloured clothing. The third was around 5ft 7in, of medium build, wearing dark clothing and a black and white baseball cap.
Anyone who can help identify the men is asked to contact PC Claire Parsons on 0845 60 60 247. Or, you can give information anonymously to Crimestoppers on 0800 555 111