Are you in West Yorkshire by any chance? I like the shop, looks like it will be a usefull size when finished, you have done the right thing with the roof, I have a flat roof on mine, and it has been nothing but trouble since the 70's when it went on! I am on with a refurbish on my workshop, well rebuild would be more accurate, but I am coming to the end of the major work, thank the lord!
Phil