While sitting down to eat one evening, a chance remark triggered Jo and Nathan Birtle's move to a more compact London home. 'After Nathan commented: "We appear to have carved out a lovely one-bedroom flat from our five-bedroom house," it really got both of us thinking,' says Jo. When the couple bought their Battersea property in 2001, they were initially thrilled that it had so much space for themselves, their son Hugo and an au pair. However, when Jo stopped working and, at the age of 13, Hugo went to boarding school, the Birtles began rattling around in their property.