Hi there, congratulations on your purchase, I'm sure you will love it.
I managed to get the dealer to throw in the windbreak for me, I told him it was a deal breaker, like you say, makes you wonder why it's not standard.
I treat my roof with Autoglym and it does a fantastic job of cleaning and proofing the roof, I can thoroughly recommend it if it is available over there.
I have seen those suitcases for sale that are made to fit the Mini Convertible boot, they look good, though a little expensive. The only thing that puts me off is that they don't come with wheels.