I think my idea is to build it in steel just to test the theory and process of construction (I also have loads of 20 and 30mm box, 3mm wall, kicking about), although I fully appreciate it will be overkill at the size I'm looking. So idea is to build a small, desktop build but with the same concepts as the larger one I'd *like* to do one day (in another property, no doubt). But conscious I don't want to get too tied up with the construction/planning that I lose interest and it all dies a death. Having said that, I'm pretty determined in most things, so.... :-S

I'll do some more reading, mull over some ideas - and of course always value other opinions (no offence Jazz, I totally get what you're saying!)...