unless you make it yourself (which is something i'm dying to do one of these days), you're going to be hard pressed to find a condiment out there that doesn't contain sugar in some amount. however, i don't think what you've got is mayonnaise if the carb count for a 100g serving shows as 1.5g... i think what you've got is "salad dressing", which is meant to be sweeter than mayonnaise and is sold in the same section of the supermarket.

look for jars that are labeled "mayonnaise" and whose nutritional labels show 0g of carbs. you may see sugar in the ingredients list but it'll be WAY down among the last 2 or 3 ingredients.

there's always a chance that the hellman's mayo sold in london is different than the hellman's mayo sold in arizona. but you should still be able to find 0 carb mayo somewhere.