Who sells on the yard, and why
Two kinds of seller bring vehicles here. Banks and non-banking lenders sell vehicles they have repossessed, which they must dispose of in a way they can later show was fair. Transport companies and fleet owners retire a batch, ten or forty at a time, when the fleet turns over.
Both have the same problem: a handful of known buyers is not a market, and a thin market is how a lot goes for less than it was worth. Putting the lot in front of the register's buyers is what the yard is for, and the audit trail is what lets the seller's own people sign it off.
This is why a lot's history reads the way it does. Every bid, every amendment and every acceptance is written once and can never be edited or deleted, and the receipt at the end proves the sequence. That is a feature for the seller and a protection for you.