I don't think Wyevale grow their own plants, they just buy in bulk and sell it at high prices. The high price covers the price of the waste. I used to go to New Covent Garden and buy direct at prices you could only dream of, 50 box balls in 4lt pots less than £200. Repotted to 5lt pots, used in a show garden then sold on at £15 each. Most of the plants for sale in garden centres and supermarkets come in daily from Holland, rebranded and sold as if they were grown in GB.