George meets Matt and Kevin, whose 1930s home stands out for all the wrong reasons. Sitting alongside the elegant Victorian and Edwardian properties in south-west London, this three-up, three-down is ugly from the outside and even worse on the inside, with dark, dated and badly designed spaces. Architects Katerina Dionysopoulou and Billy Mavropoulos are brought in to make most radical transformation on the programme to date - but will their wildly ambitious poured-concrete extension prove too innovative for the owners?