My Garage is about that size, kept it small to stay away from planning issues/regulations. Not that I've built it sub standard, it's just when you go much bigger the authorities get involved and the cost (their costs) skyrocket.
Given the choice I would have built it half the size again.
eg, with machines down each side you can just squeeze my car in, well until the new lathe that is.
A touch wider would have made the world of difference. Say 5 or 6m and 8m long.
I will sneak in an extension at the back later
