Thanks for the warm welcome.
Unfortunately my house is a dormer, so there's pretty much no attic space.
Yes of course OO gauge. I'd already done a bit of research and realised that it was of course possible, and watched a bunch of videos on youtube.
At the moment I'm still in the "research" phase. Also trying to get a few bits and pieces together to actually build it out.
One of the problems right now is that wood and most other building materials are insanely expensive. I suspect I'll be looking at architectural salvage, but I'm absolutely hopeless with DIY, so it'll be kept fairly simple!
thanks again
Michele