Taking a long shot posting here, but can anyone give advice on how to find out property values?
It is indeed a long shot. The property market in Greece is relatively undeveloped and values are often nothing more than the opinion of the owner and a starting point for negotiations.
There are plenty of real estate agents with internet sites and, as is often the case, Google is your friend.
Exactly as Philhellene says, no property value guide as such, especially in smaller towns & villages where no 2 properties are alike. The initial asking price for any property is often based on a figure plucked out of the air by the owner, no matter what agents may have advised them to ask. It is also very difficult as you can look at a range of properties in the same area & the logic (or lack of) the asking price usually makes for a very strange comparison.
There is some sort of guidelines as to the value per sqm in different areas of Athens, but this doesn't really seem to work the same way elsewhere. The same applies to plots of land, they will be sold for whatever someone is willing to pay for them!
Definitely spend some time using Google, you may well find the same properties on more than one site, & don't be too surprised if they show different prices!
Thanks for the replies. Google it is.