Hi there!
Like me you have to find a caravan that suits your car. I was in the same postion about 6 months ago. As I only have a 54 plate Ford Focus C-Max 1.8 Zetec I was quite limited in what I could get, however there are caravans out there which are quite light to tow.
As your car has a kebweight around 1170kg your 85% match will only be 995kg. As with my car you have a 1200kg towing limit on the hitch so you'll be within this. When selecting your caravan you need to ensure that the Maximum Technically Permissible Laden Mass (MTPLM) figure is as close as posible to your 85% figure of 995kg (Best not to exceed it though)
The only 'new' caravan that falls into this bracket is the Caravelair Antares Luxe 425. This has an MTPLM of 970kg and would give an 83% match. You are not restricted to new caravans though. You'll find that these tend to be quite heavy anyway and that the 'older' caravan can sometimes be a lot lighter.
If you were towing my 'van for instance, a 1994 Swift Rapide 440 GXL, your match would be 85.5% as its MTPLM is 1000kg. As with my car though you will find that it will come along fine on the flat, however as soon as you hit any sort of gradient you'll be giving the gearbox a lot to do!! As soon as my car is paid off i'll be getting shut and getting a nice diesel!
Sorry to drag on so long!!