Waterloo Medal: Victory | The Royal Mint

Very debatable. Edition is 2950, which is not low for this sort of thing. Melt value is only £50 - maybe $70, so you are relying on a massive interest from the modern collector's market, which is unpredictable. It may 10 years or more before it gets back to the purchase price on the open market, and with the world economies in such disarray, who know where we will be in 10 years? Gold is still the safer bet for investment purposes.
A dealer said to me, early on in my collecting, "Anything that is made to be a collectable almost certainly isn't."
However, every now and then an item bucks the trend...