I believe that freezing tends to ruin the membrane, [I would have used a slightly more descriptive term, but since the language clampdown on the forum!]
Mine normally lives in "The hovel", an outdoor brick store, but it's inside now, I've got it installed in the bathroom, it can go outside again in the spring.
My pump is bolted to a plate of aluminium that is in turn fixed to
the hosereel, and connected to the "Varistream" by a non reversible plug/socket.
Lifted out of van at night, and brought in, together with poles/brushes, and belt with tap attached - gloves near the radiator for the night, and that's it!
Baldeagle