Property owner wants to get the best price no matter who approaches them. Last price on road will give you a good idea but other factors such as aspect, no bedrooms, extension, attic conversion will of course need to be taken account for.
I was house hunting with a friend in the estate and we asked a neighbour washing the car what they knew about other houses that were for sale recently. Neighbours usually know the last sale value, it lets them know what the current value of their house is.
If you are interested in a particular area keep an eye out on all houses for sale. Drive around the area, contact all EA and see what the houses achieve.
Good luck.