Prices in Britain won't change, but if you're using dollars to buy things priced in pounds, it simply costs fewer dollars per pound. But here's the thing, retailers bought their stock weeks or months ago, so they won't see cheaper prices until they buy new stock. Again, the pound isn't down that much and it's at the same level it was in February. Further, if you're buying retail from an American importer (e.g., Smokingpipes), you're not likely to see any price difference at all. American retailers, unless they decide to compete with each other on price, have no real incentive to lower prices until there's a significant and sustained drop in the pound versus the dollar. Until then, they'll pocket a few extra pennies on British tobaccos, but only on stock they purchase in the future, not stock they've already bought.
Shorter: don't worry about it. If anything, the price of FVF will go down a little bit rather than up.