Sadly yes. There's a surplus shop down my road and right after I posted that I went to check one out. They are enormous. I could climb inside and have room to spare.
We use baggu cloud bags in our baskets. No good if there's no platform, and not 100% waterproof. But claims sustainability, nice colours and quite practical with outside and inside pockets. Also does definitely not look like a cyclists bag ;-)
Those are huge, no?