Hiya,
There has either been a misunderstanding or a blatant lie on the salesman's behalf. The Peugeot Passport Scheme is their brand name for PCP (Personal Contract Purchase) much the same as Ford's Options or Vauxhall's one (Choices?).
One of the advantages of this type of scheme is that at the end of the term you can hand the car back (providing you have stayed within the mileage band you declared etc) with no financial penalty. Until then it is virtually the same as a normal HP agreement.
You're going to find it difficult to prove he lied to you because you signed the agreement. The only way you can hand the car back before the end of the term is, as you have discovered, by paying half the total amount payable or by selling the car to somebody who will be happy to pay the settlement to Peugeot Financial Services.
One thing is for sure, there is no clause for you to hand back the car at any time with no penalty.
JJ
You gotta tie yourself to the mast my friend, and the storm will end.