There are two reasonable approaches here: wait for reliable completed prices, or start now with the listing records that are available. I would combine them on a small scale.
Take a few recent completed sales, rebuild their original listing dates, price changes, withdrawals and relistings, then compare energy performance only after location, villa type and general condition are visible. If closing prices cannot be obtained, the result can still show seller behaviour and price-cut timing, but it should not be presented as evidence of what buyers ultimately paid.
Take a few recent completed sales, rebuild their original listing dates, price changes, withdrawals and relistings, then compare energy performance only after location, villa type and general condition are visible. If closing prices cannot be obtained, the result can still show seller behaviour and price-cut timing, but it should not be presented as evidence of what buyers ultimately paid.