The experts reckon we lose the equivalent of two coats of varnish a year to UV rays even with UV protected varnish so you'll need to be looking to put at least two coats on a year just to keep up.
Always be prepared to remove deck fittings, hand rails etc to maintain varnish levels underneath them where moisture can hold on. You also get to re seal them properly - prevention is better than cure.
Investigate leaks and black areas as soon as possible, I have seen missing chines and bulkheads with the bottom rotted away because of a leaking handrail that was deemed unimportant and left.
Wet sheds are a bit idealistic though a boat badly stored in a wet shed can deteriorate faster than a boat stored well in the open. Ventilation is key. Let your boat breathe both inside and out and give it a chance to dry out when it gets wet. You always leave the fridge door cracked open when you leave a boat, think about windows, cupboards and drawers.
Cracking boat Ray. There will be a lot of pleasure to be had varnishing that little lot.