Looked a bit on tinterweb and not found anything, so:
I’ve got a Timbuk2 Courier style bag that I use day to day.
I cycle to work occasionally, the bike I use has a pannier but I have no decent bag, tried a cheap basil bag that fell apart quite fast but gave me enough of an idea that I want to use a pannier bag for the commute.
As I already have a decent enough bag and don’t feel like plumping up £90 for another bag, is there a net type mount or something that I can use to put the courier bag onto the pannier and maybe put shopping and stuff in at other times?

bunji it to the top perhaps ?

Yes tried that, it’s OK but got this idea in my head that a cargo net and some sort of backing that mounts to one side of the rack would be good, or a big pannier type bin (waterproof not essential) so I can pop the courier bag in there when riding to work and on days that I stop for shopping I can fill it with the shopping and wear courier bag. Was just looking to see if such a thing existed.

plan … buy a bucket – drill some holes and zip tie it to the rack – cargo net over the top ……remember to put drain holes in the bottom 😀

A bucket?! 😀 might try and make something like that at this rate.

A pannier without a rigid back would be pretty annoying I reckon- you could put something inside though I suppose.

The sort of thing i’m thinking of is bascially a rigid board with a cargo net or something on to strap a normal bag to. Seems like such a thing doesn’t exist.