I am not sure whether the quoted price difference is for a single speaker or
for a pair of speakers. But either way, the amount does not sound right to me.
In the following, I will assume the difference is for a pair of speakers.
In the Netherlands the retail price of a pair of 803 diamond is 9000 euros.
Which means you would pay only 10-15% less for a 2nd hand speaker from
the previous generation. This is just not right.
Firstly, when buying 9k euros speaker that are new you should have no
problem to get 10-15% off the retail price. If you can not get such a discount
then just go to another dealer.
Secondly, when buying (from a private person) 2nd hand speakers that also
happened to be from the previous generation you should not pay more than
60% of the retail price of the equivalent new model. If you buy a demo model
from a dealer who also offers some significant warranty (1,2,3 years NOT 3
months) then you should not pay more than 65-70% of the retail prices of the
equivalent new model. This is especially the case when considering very
popular brands like B&W.
However, since you do not mind buying 2nd hand speakers (I do not mind
either) my advice would be to look for some Wilson Sophia 2 or Focal Alto Be
speakers. Both are much better than the 803 diamond or 802 diamond for
that matter. The Wilson should cost you about as much as a new pair of 803
diamonds, the Focals are cheeper (around 7k euros). Of course, there are
many other options.
Finally, I should say that if you plan to keep the speakers for a long time than,
given the price point, 1150 euros is not that significant.
Good luck and keep us posted!