Hello Adrian,
I can't comment specifically on your choice of car, as I haven't driven one, and you don't tell us exactly which model.
The exact model of car is important, because Citroen make several versions of the DS5, with different engines, and consequently the it does affect the cars towing capability. So to get the correct details we really need model, year, engine capacity and power, transmission, trim level (eg, S, GTI etc) and body style.
I have looked at a data base which lists most cars details, but for some reason the DS5 details aren't complete, for example I can't confirm your claimed unladen weight, and the permitted towed weights vary enormously for the 2.0L based engine. (from as low as 800 to 1500kg)
However based on the figures you give, the towing ratio comes in at 92% which is possible especially as you have towed before. I believe it is sensible to away choose cars and caravan to gave a small towing ration as possible. The industry suggests trying to keep below 85%.
Not perhaps a choice for novice tow-er but far from impossible.
Do double check the towing limits of the car you are thinking about, you should also double check the cars Gross Train Weight limit which might limit how much weight you can have either in the car or the caravan.