Original sentence: "flats" can be council tower blocks, off-plan buy-to-let purpose builds, 1960's purpose builds or converted Victorian mansions etc.Recent press estimates that off-plan buy-to-lets have halved in value, thus reducing all values.The Zoopla estimate and a recent estate agent valuation of a property differed by £28,000.Utter fantasy that is distorting/abusing the market.What they fail to understand/disclose is that the local authority information is for such a wide range of properties that it makes its application to one property completely meaningless e.Zoopla appears to be trying to cut out the middle men by allowing users to offer their properties for private sale ("tempt me"), while relying on estate agents to provide valuations.Zoopla proportions the 2 averages and factors the purchase price to provide their estimate.Zoopla then cross references the date and postcode with Land Registry House Price Index to determine the average price for a particular local authority at the time of purchase;.Zoopla then cross references today's date with the Land Registry House Price Index to determine the average price for a particular local authority (bear in mind Land Registry data lags marketed property due as it is based on purchase completions);.Zoopla's own valuation estimates are wildly inaccurate and are based on flawed data: their valuations rely on the following:.user/property owner enters purchase price (for which they may have over/under paid) and date;