Spent a little time this morning getting to grips with Homestyler from Autodesk. It's a free to use website that allows the user to plan and design their own rooms. You initially work in 2D pulling the elements you need onto the customisable floor plan. Adding doors, windows, furniture, floor coverings, etc. Then click the 3D button and see your design in all its splendor. You can also take a snapshot and save it to your computer.
Looks like a really useful resource for use in Yr5. Would fit in beautifully with 2D and 3D graphical modelling.