Your shed will give them adequate protection from the weather, Bainliam, but the lack of light will destroy the plants. Assuming that the plants are not especially tender all they really need is overhead protection. Can you construct some sort of shelter against the wall of the house? Maybe some piles of bricks or blocks with sheets of glass/plastic over the top. If you can put the cover at an angle to shed rain and snow this would help. Finally, the cover needs to be weighted down so that the wind doesn't lift it off. Picking small shards of glass out from amongst the plants is tedious work - I've done it too often.

they will be ok if you have plenty on light in the shed i.e. big window or artificial grow lights, but as B.H. says lack of light will kill them very quickly..

Many Thanks for your replies Bulbaholic and Surreylad - most appreciated