Advice needed...

[Grant]

A lie detector is what you really need.

[Wolfgang]

give him the money back and look for another buyer - otherwise only the lawyers will earn a hell lot of money. Private sale means always cash in total (please check in before if the notes are not fakes...) then handing over the goods. test drive only at your location - max one hour with you on the passengers seat.

[AH1951]

Dependant upon you both having accounts at the same bank, online transfers are instant and convenient.
That's how I transfer money to my wife when I'm working overseas.
Zero transfer fees.
I think physically carrying £50,000-00 or more in folding money on your person is a bit unwise.

[kenny38]

This will never end, even if the buyer does pay you all outstanding monies and takes car home. He sounds obsessive and fearful of "paying too much". I will say within 2 weeks of taking delivery he will be on your clacker demanding reparations......and you will be surprised what "you said to him" during negoitations and have not honoured, etc. This type of buyer is found in all shops such as carpets/furniture/electronics when customer pays a deposit and fails to pay balance while making spurious complaints. Eventually vendor gives up as going to court is not worth it. Some times some buyers are just a bit strange. Even if you extract all the money from him before handing over the keys IT WILL NOT BE THE END OF THE MATTER. Some buyers WILL go to court seeking "redress". At various times I have been victim of this type of behaviour (usually an AsIan type) and have steadfastly refused to deal with them. Take my advice. Give him back his money and do not even let him pay all outstanding amounts. I sense a fraud. Do not let him test car alone and if going on test try to have some one in back "seat" as backup. Walk away now and you will be avoiding a lot of angst later. He may sense a sort of eagerness/ desperation in your desire to sell......Good Luck. Kenny38