...that I have been using for a while and found very helpful. Apologies if it's already been posted and I missed it.
www.property-bee.com
It's SO cool. It gathers data every time anyone using it looks at Rightmove or other property sites, and logs changes in price/details so you can see when a house was first spotted and if there have been any reductions. Very quick to download.
It's already enabled me to catch out an estate agent in a big fat lie .