It's taken me ages with the small amount of time available and little help, but I've been enjoying the benefits of my new shed/unit the last few weeks as it's more or less done (in fact these were taken a while ago, and I've sorted out some of my spares since then).
Decent light, square walls and floors that you can also sweep properly, space, storage, and best of all, a separate area at the back where I can store my bikes well away from any other work I might be doing. This area is also independently secveured with a massive door and stud wall, so my bikes are also safe. I also had the blokes who do fabrication a few units up (handy that) make me up a steel door for the entrance, and it's bolted on the inside of the simple wooden door that faces the world. I bought a cheap but loud radio/iPod dock with sub woofer, so can now shut myself away in peace with my favourite tunes (currently a Swedish band called Hellsongs) and get on with working on bikes. Bliss.