How much is a Dumpy Bag?

Mr P ordered 2 "dumpy bags" of barn dried firewood.  "How much volume is a dumpy bag" I asked.  Mr P had no idea. Now we know.  As yet we have no wood store. I can see a building project for Mr P.   I stayed in, Mr P went walking with our guests.  The highlight of my day was discussing dodgy hips with the wood man. Oh dear, I can see now there is washing on the line.