From my understanding, if you accept, then he has 21 days to come up
with the money. If someone else offers you more in that time and you
decide to sell, then his bad luck.
Roughly the same as a house. You can
put in an offer on a house which is accepted, but before you sign/seal it someone
else can offer more and sign/seal before you and walk off with the house.
From what I can tell, by you accepting, he gets a guarantee that if he can
get the money in that time, then the price is fixed (ie, you will not ask for
more when it comes down to a cheque in 18 days). This also allows him
to let the finance company know the price details etc...
You could accept it with the condition that "if someone else offers more
then the sale will be made to them"
