Skog, Maybe if you got a hinged flap water tank filler (from Camec), you could put a flap on the outside of your canopy, lift it up and hey presto, you have air!
I think you are getting the same canopy as i have from memory, so the corner pillars are hollow, so you might be able to mount the tank on the side vertically where the fittings would be concealed from the outside. There is also quite a lip over the tub at the front, so it might be wide enough to mount the tank under the front window without getting in the road as objects rest on the lip. Or mount a flat cross bar onto the bolts that hold the roof rack bars to the roof and put your fittings into that, no holes either.
The good thing about that one is it will get in the way and you won't be able to load washing machines in when you are asked to help somebody to move
Some of them are heavy I found!
Rod