It's the fourth of 8 heats as 3 new designers battle it out for a place in the quarter final and the chance to win The Great Interior Design Challenge. This time our amateurs are in South East London on the River Thames, taking on sitting rooms in neighbouring homes in a beautiful Converted Mill. Architectural Historian Tom Dyckhoff discovers the history of the Mill and the local area, as Judges Sophie and Daniel decide who has the winning design. 55 year old Housewife, Dee, from Whitstable in Kent, is hoping her French Farmhouse Style will win the day, but finds resistance from her client. Vintage enthusiast, 40 year old Emma from Manchester is also working hard to persuade her client on aspects of her boat house theme. 30 year old Shop worker Luke from Oxford, is keeping his client happy by turning his creative skills on making cat Furniture for his African themed room. With upcycling challenges and tricky clients the designers have got to convince everyone that they have what it takes to be an interior designer. But with only 48 hours, £1000 and the help of a builder there's a lot to do and only one designer will be able go through to the quarter finals.