English wine: discussing the challenges of a growing supply

UK volume sales of both still and sparkling wine are in decline. Analysts predict still wine sales will fall by almost 11% over the next five years. However, consumption, production and planting of English wine are all increasing. 2018 production bottle equivalent is up by circa 180% with hectarage under vine increasing by 83% since 2015. It is predicted there are roughly 7-8 years of U.K. sales currently in stock with around 55% of plantings having no wine currently for sale. Considering market decline, assuming the market is one of monopolistic competition, and noting only 8% of English wine is exported, supply is grossly outstripping demand. How will this excess supply impact the market and how should it react?