The average price increased by 1.5% with Chelsea and Kensington the highest performer with a rise of %, according to the July Knight Frank prime central London residiential index.* It also shows thatn house prices are increasing faster that flats, increasing by 1.9% in July. Price band performance is similarly divided with properties under £2.5 million rising by 5% compared with 3.9% for properties worth more than £10 million.