After having been quoted £271 pounds to have the module for the folding mirrors. I went onto Facebook (Thank you Big Al for the tip) and reported to Mazda my feelings over the matter of being charged £158 pounds over other dealers prices, and this is what they've come back to me with
Dear David sorry to hear about the frustration with Stoneacre Mazda, we will raise this with our dealer operations team. Each dealer is privately owned and has their own labour rate so this will vary from dealer to dealer. Each dealer has a guide labour time for each accessory also so the only difference should be in the hourly charge. As advised we will raise your feedback with Stoneacre Mazda which we thank you for.