Probably the most common loft conversions happen on these types of houses. Check the options here and you will find something similar to what you require for your conversion.
You could say that it was the Victorians and Edwardians who built the capital, and they built quite a range of houses - from multi-bedroom villas in estates which have since become conservation areas to artisans cottages which still fit today's families.
Some have cavernous rooms and high ceilings whilst others have been carved into tiny flats. What most of them have is character, which is why we are often more fond of them than we are of later developments. Usually you will want to keep that character (and so might the council!) and there are often a lot of options to choose from. Browse the links to the right for some ideas - and don't just stick to the one for your property. Several configurations are equally suitable for a wide range of London properties.