The responses from the Dalek Forum were helpful. Firstly, they suggested that we build the whole skirt unit separate from the base with the wheels on, so it could be detached for going through doorways. I got sent a link to a video of a guy and his kids building one of these things in a day. I had to go and have a lie down just from watching it.
Anyway, how hard can it be? Come, sit upon the carpet, and I'll tel you.
First, I used my last large sheet of wood to draw out the top deck - the top of the skirt unit.
It wasn't that hard, so I cut it out. Most of the cuts were pretty close to the lines this time.
The plans say the skirt unit is 68.6cm tall, so I cut a support that was 68.6cm tall and screwed it to the top deck. Do you see my mistake, folks? Don't worry, I catch it later. Meanwhile, I do not have a sheet of wood large enough to make another base unit. I used the only one to make the first base unit, that this base unit is going to sit on. I can't ask Mrs Dim for more money to build another one of the things I just made, because she might give me one of those looks, and right now I feel I am lacking the moral high ground. The obvious answer is to construct the base out of several planks of wood that I do have. Best if they were all the same thickness, but that's not how the Universe works. So, collect planks and try to glue/screw them together into a useful configuration:
Look, this is actually quite good for me. I've cleaned up the workshop, and I'm using actual wood clamps and brackets made for screwing into wood. And wood glue too. And I'm still following the plans... Mostly. There's a lot of .5 and .6 stuff that gets...mushy in the real world, because my pencil isn't sharp, or the ruler slips. Maybe when I get the fourth plank on, it'll look better.
Oh yeah. We're in the big league now. It's at this point, when I go to cut out the two other supports for the top deck, that I notice the mistake I made earlier. I didn't take the width of the top deck into account when I cut the first support, so it's too high. Luckily, I still have time to cut down the first one and make the other two the right height first time around. Let's put it all together!
OK! Now, I just need to cut out the section of the bottom base to allow feet through, Fred Flintstone style, and cut a hole in the top deck so someone sitting in the dalek has somewhere to put their torso.
Alright. Not bad for a day's work. I know how I'll build the seat, and Eldest Weasel has been cutting out panels, so fitting them is really the next stage. They're going to look rough as old boots for the longest time, because we'll have to reinforce the joins on the inside, then bondo the outside joins and make good. I have no illusions about the blood, sweat and tears this will require. But tomorrow is not a building day, and I'll only have time for a little on Monday, then who knows when I'll get back to it? Ah well...