Reminds me of one I saw once. After I made my excuses and jogged on, I could make such an objective list of what was wrong with the vehicle, what was likely also hiding, and the exact same dealer selling for a mate BS, I felt a lot better for walking away, for sure.
If in doubt, bug out. Just a shame buying used cars is such a massive waste of time overall, but all worth it is you find the right one eventually.
Agree with someone here, not officially selling it through a dealership means it is not covered by the trading standards, and even if you do buy from a dealership you may always end up having to drag them at cost to a small claims court, so this is no peace of mind really.