This week Sarah helps two aspiring property developers in London. Trying to make as much money as possible from your property is one thing, but filling a house with rooms till it bursts at the seams is quite another. In Hendon, Shaffi Ahmed is convinced she can maximise her rental income by cramming ten bedrooms into a three-bedroom house, even if that means putting them in the attic, in the garage, or even in the shed at the bottom of the garden. A few miles down the road in Acton Derek Gallimore is also trying to increase his rental income by modernising and adding rooms; but will it make any difference when his house sits right on the busy A40?