@crowriver: I took them off the Elephant Bike in the end, mainly because I wasn't using them to their full capacity, and I found they weren't that practical for commuting as they didn't keep any weather out (so I put another pannier inside them...). They were heavy enough that I didn't want to pedal round with them all the time. For what I normally use the EB for, the front box is usually enough.
If you're regularly carrying lots of stuff, they are very good and capacious. They are absolutely not weather proof: the lid doesn't keep the rain off and can blow open in the wind. I got some super-strength self-adhesive Velcro and put that in a grid pattern across the lid and body so I could close the lid in different positions. They do need a stiffener inside to keep them from sagging. If you have a trailer hitch on your back axle you'll also need to lift the panniers above the rack (I used a block wood, which added to the weight).
I don't regret them. They suit the bike very well, and fit it nicely. Ordinary panniers look a bit silly on the long rack. I will use them in future, just not all the time.
I've since found that two Ortlieb City Rollers will fit on each side with only a minimal amount of heel strike, so that's another option.