The Natural Philosopher typed:

"Why would someone want to sell
their car at auction?" and the cynical answer then pops up: "Because
it's probably a lemon and they don't want the buyer to be able to
find out what's wrong with it before they buy it." Call me a cynical
old so-'n-so.

No. A lot of cars go to auction that have come into the trade as
p/exes, and are below the standard of the dealership.

If you atke a 12 year old Volvo and trade it fopr a newer one, in a
dealership,. they will take our old one and throw it straight into
auction,

Yes but do the maths on this, I live in a rural part of the country the
nearest auctions
for cars is 60 mile away so its going to take two chaps x hours and plus x
amount of fuel to take a £500 car for auction, or £50 for a breaker to
squash it when they could be selling a 25k new car.
the local market is awash with older Mondao/Cavalier size cars nobody wants
them, everyone wants new or nearly new clean Low mileage FSH cars within
this sector.
4x4s and small cars still sell ok down here even Metros! Strange world.
IMHO The Volvo 7 series is the most reliable practical versatile cheep to
buy throwaway skip on wheels car ever made. :-)