I bought a Carradice Barley and Bagman Quick Release with Sport Support (catchy name) for my Bob Jackson World Tour at the London Bike Show this month. This included the new bag fitting that uses a bracket fixed permanently to the bag with cable ties, rather than using the usual leather loops - it makes for a much more solid and secure fit with virtually no rattling around or vibration.
With my Brooks Team Pro saddle, which has fairly short rails, on a Nitto S65 seatpost, which has a fairly large clamp, the bracket is a close fit though and would not have fitted if the saddle wasn’t almost fully back on the rails.
The Carradice Barley is great, it’s actually a “Barley Special” with an extra leather panel sewn on the base. It’s pretty compact but with a quoted capacity of 7 litres it just fits my 11” MacBook Air, a change of clothes and the usual basic bike tools, and of course it’s so well made (by Priscilla).