Just received the following comments.
I am incensed that you classify Aberdeenshire as "remote Scottish highland". Aberdeen is a major terminal for the oil & gas industry, Peterhead is the largest white fish port in Europe and the area as a whole has excellent communication to the south. The West Coast residents have started a blacklist of companies that charge exorbitant rates for delivery, the idea is spreading and the list growing. You, no doubt, will blame the carriers but by using those carriers you are losing business. If I can get 25kg of dog food delivered from Hertfordshire for £4.95 it ought to be possible for other companies to charge similar rates.
I pointed out that if he ordered one bag of Fertile Fibre Compost he would only have to pay £1.20 extra.