Thebag no useful advice to add as we are a long way off starting the actual build so I don't have any first hand experience, but sending you lots of support and I hope some of the other advice you've received helps.
Brandnewhouse thanks for the book tip, I'll add it to the next Amazon order. There seem to be loads of good project management/gantt chart apps around, which seem sensible too, although I suspect nothing beats an A1 piece of paper which everyone can see!
Humptynumpty nice doors. We will be having glazed downstairs as much as possible too, to get the light through. There has been lots of discussion of glass bricks or those narrow glass strips along the top of internal walls to let the light in (which have a name, which completely escapes me at the moment), but no idea whether it will be within budget/feasible. Our house is terraced with a south facing front and north facing back, so the aim is to get as much light from front to back as possible.
We had a wildlife survey done yesterday (required in our local area for conservation reasons), by someone very local. It took about 8 minutes and cost £230. Even if it takes an hour to write up the report, I'm thinking that's a fairly profitable enterprise!
DH and I are going to start making a shortlist of builders to approach for quotes in a couple of weeks and start asking initial questions (like 'when could you start' and making sure they can manage contractors) - we want to get as much prepared as possible during this 'dead time' while we wait for planning permission. Need to get structural engineer quotes too.