Hi Neil;
I am not experienced at leaving assembled bents for a winter but I had some thoughts. You are running the risk of mildew growing on the timbers. Also as timbers dry they can twist and shrink so some readjustment of the joints may be necessary before and during the raising.
I do not have any answers to avoid these things. All I can do is wish you well.
Please post some pictures when it is up!
Jim
