So, I've replaced my Bagster 12 litre tank bag, with the offering from SW Motech. It's from their Evo range, and I've gone for the 5 litre option which extends to 9 litres. Perfect for my needs, though there is bigger bags available. Fitting is very straight forward. Overall, I'm very pleased with it. Expensive, but good quality generally is. Goes nicely with my SW Motech Blaze Panniers Just need to sell the bagster now.