Hi Paul - the Land Registry now provide all of the price paid data month by month for all sales across the Country. http://www.landregistry.gov.uk/public/information/public-data/price-paid-data you'll have to manipulate the data yourself (sort / filter for your authority) but you can then do what you like with the data.
Another resource is CLG quarterly house price data (Table 581 gives data by district) but there tends to be a lag with that...
https://www.gov.uk/government/statistical-data-sets/live-tables-on-housing-market-and-house-price
The Land Registry also shows data in the their HPI (search the index) on a monthly basis but only by Region, County and Unitary (not for all the other Local Authority areas).
Rob Searle (Dixon Searle LLP)
