We went to a Home Building and Renovation Show to try and get both ideas and guidance. There were various seminars going on telling you how to make your house Eco friendly or how to self manage a project etc. Sitting in on these proved to be an eye-opener but has not discouraged us. We were slightly swayed by their estimated figures but we are thinking that if we can do much of the work ourselves then we should be able to keep costs down. The only trouble with doing it yourself is you need to have the time to do it!
In terms of the existing house we are currently in the process of (as in we stand at the door, saying "We need to do something about these rooms") converting the two smaller bedrooms into a bedroom (I know, not much of a conversion) and a bathroom. This means re-laying the floorboards that came up after the new Immersion Heater was put in, taking down the current dividing wall and putting up a better one, then getting the bathroom fitted, the walls plastered, the hole in the wall filled (which is nice and airy but not so great when it rains!) and carpets/flooring fitted.