Are you able to order from GW Little there? I'm not sure if they have buddy belts, but they have a similar style and as long as the harness isn't custom, they have an excellent return policy so you can try different sizes. We use the Susan Lanci step in harness
and I love it. It's pricey, but I doubt I'll ever need to buy another harness. It's similar to the buddy belts in that it fits behind the legs, so if you get one that fits well it would be close to impossible for a dog to escape. Plus, it's so soft and thin!