How to reevaluate property value in Greece

HI,

I am looking to apply for Greece golden visa but I need to clarify how authorities value property value. I have an apartment in Greece that I bought a couple of years ago and its value has increased 2x since the purchase. Is it possible to get some official document (attorneys office, cadastre, or similar) to state that this apartment is now valued much more now.
I can then buy the second apartment of much less value in order to meet 250K requirement.

Thank you