You close this crossbody bag with a twist lock. It only comes in one colour, brown, but it does look quite neat.
From Selfridges
Mulberry Womens Brown Chestnut (brown) Alexa Leather Satchel Bag 25x33x18cm - BROWN
John Lewis & Partners
Mulberry Alexa Heavy Grain Leather Shoulder Bag
This product is also available at 2 unverified stores.