Are you looking for something official on letterhead etc - or just for yourself to have an idea?
If needs to be official probably best to go into a Peugot dealership - or at times they accept the OMSP value of the VRT tool when printed (provided the value they put on it suits you).
Either way... all dependent on exact model and spec, mileage, nct etc... As a general rule - 2007 cars are worth little to nothing unless they are something special. If an average model with average mileage, but has good tyres and long nct then probably worth 1200-1700 depending on model and spec (you will see them advertised higher, but they are not making that money). If high mileage, or lacking nct, or needing tyres or other money spending then value can be between 100-800. Auction prices across engines and grades range between 150-800.