Despite some great initial success with free Sweet Home 3D, that quickly gave some great mock ups, I found from quite a look about that most cheap or free packages are:

• Very USA based in terms of the look and feel / standard furniture options etc.
• Limited on what you can and can’t do.

This matched the answer given on http://www.homebuilding.co.uk/community/ask-the-expert/Which-DIY-software-package-should-we-use-design-our-new-home pretty much matches this:

“Perhaps the best CAD package is Arcon’s 3D Architect (around £200) which is quite intuitive and more sophisticated than the others, although quite expensive. In truth, the packages – such as Ideal Home 3D Home Design – retailing at around £30 tend to be much of a muchness.”

So I’ve on-line purchased (£180) and downloaded Arcon 3D Architect and we’ll see how that goes !

In the end, the architects I chose, ARCO2 used Sketchup, so I had their generated Sketchup file for the house. Which was amazing.