I think the dealerships get them from LRNA when they are building or remodeling the dealership. That is how all the new or remodeled Land Rover Dealers were supposed to be (no more lodge theme). I'm not sure if they are still mandating this or not. Anyway, all the promotional posters, transparencies and films are sent from LRNA to the dealers, so they probably have no idea where LRNA sourced them.
"I have taken more good from alcohol than alcohol has taken from me." - Winston Churchill