The British are extremely proud of their homes. It is very rare to move into a new home and feel everything is perfect - there are always adjustments we want to make to fit our homes to our needs.In Hastings, the Brett family want a self-contained teenage den in the garden and a Juliet balcony. In Dulwich, Nitin Nagpaul is spending £350,000 to renovate his entire house, but there is a late addition - a big family conservatory that will complete his vision.So how much will their changes end up costing? Crucially, will the changes boost the value of the homes? And will the planners allow such idiosyncratic additions?