ive never ordered a poly online purely because of the spines, on the ride home from the lfs 20 mins down the road they pop the bag. i transport them in a coolbox just for that reason.
if you decide to go ahead then i would make sure they understand to use a heavy guage bag or a plastic tub. just to air on the side of caution.
i would look at wildwoods, tropicalfish2yourdoor and trimar.
Hi andy,i recently got two congi bichirs from dan at tropical imports and all i can say is faultless,this was the first time i had ordered polys online so was worried about spending my £120 but they were fine and were bang on time.what kind are you looking for?.try your local maidenhead aquatics,thats where ive got most of mine from and wharf.wildwoods are quite expensive by the way.
Id say your best bet would be aquarist classifieds there are normally quite a few ornates etc on there.
Good luck.