Buy a Barbour waxed canvas messenger bag if you want a bag that is BIFL and will look timeless. You can also send it out for any repairs if necessary. Best 20€
Barbour W's Laire Medium Leather Saddle Bag - Quest Outdoors
Barbour Essential Wax Messenger Bag | Barbour at Farrar & Tanner
Barbour Messenger Bag Leather Cotton Gray England Style Luxury Shopper | eBay
Barbour Messenger Bag Leather Cotton Gray England Style Luxury Shopper | eBay