Not Ben, but do have some Bikebins.
I Wouldn't want to use them for Audax rides, and haven't found them to be too much use as normal panniers either. The biggest problem with them is their internal shape, as it's not square / rectangular, just because something fits in the top, it won't fit all the way to the bottom, so no use for taking parcels to the PO, also as they are rigid, they will bash any soft objects like bananas to bits. They
can't compress down either to fit things / as you use stuff up, can't have anything sticking out the top.
On the + side, they aren't that heavy, if you use a pair, they give a nice level top if you need it, and they are strong & waterproof.