It was DF he told avout the 50kgs, not NF.
I agree though, you don't transport that quantity of weed while its wet, and if this 50kg is genuine dried weight, he would have been running it for a much bigger fish, not drying it out in AB's attic and selling it himself.
One thing I think we should consider with all the the other get-rich schemes he had going is that he was growing it himself. Would make sense why he had so many properties. Take 2013, at this time he owned a motorhome, the WF (and possibly other vehicles), a kiosk, an allotment and the box factory. The whole reason he was doing no gardening on these allotments but talking about insulating the buildings and renovating the basement could have been to set up a grow room. Same with the box factory. The weed he was drying out in 2007 might even have yielded from the hannover allotment.