how are you finding the blackburn frame bag?? - im about to get one from wiggle. i like its expandable bit. mines a 20" top tube so the large looks a good fit.....
I have it as well and I am quite pleased with it for the money.
I would suggest upgrading the sewen velcro straps to some light weight double sided velcro.
I’ve got a large one and like it. It’s 100% not waterproof in any way though, and it expands down a weird distance so you’re left with a bit of a gap between the bag and downtube.
A little disappointed that DPD messed up my delivery today - No Surly for this weekend's overnighter.
The Ratbike stepped in to save the day!