The temperature difference? Twofold I guess: less heat escapes - which must be a good thing - the outside of the dome no longer gets hot, plus it's easier to get up to and retain good cooking heat.
I could get the oven hot before, but it cooled pretty quickly. That's manageable for pizzas but I soon discovered I wanted to do other things, bake bread, make slow casseroley things, and for that you need more control over longer periods. Insulation gives you more control.
I really like your air vent in the base/wood store that lets air flow round your wood. I'll pinch that idea if it's ok.
Very kind Trac, very kind... re the vent, a small steer for you: though that's exactly what I intended, I've found it impossible to store wood there at a truly low moisture content. It's as if dry wood has the ability to suck moisture in from the atmosphere, and really dry wood is what you want. Dave put me onto this: you don't want to spend much of your time trying to set fire to water.
Once you have a decent fire going, you can put a few logs in the oven doorway and even dampish stuff improves that way. Really nice, dry stuff improves to a point where it almost spontaneously combusts.
I'm lucky to have a boiler in an outhouse where I can store my firewood in shallow plastic trays stacked on top of the boiler.
So, my suggestion: store some wood down there under the oven with the tools, but try to locate a really dry place about the house where you can keep your 'real' stash.