We bought it through the municipality. The standard land value was about 15% above the purchase price, market value (proven, since we resold a piece) was well over double the purchase price.
It was mainly about the equity ratio for us, but no chance.
We told the banks that we already own a plot of land, unencumbered, which we want to contribute as equity. Everyone only wanted to know the purchase price (acquisition date is visible through the land register). Our submitted cost breakdown based on [BRW] was immediately corrected by every bank.