Thanks to Duster for pointing me towards the website Tow.com. I put in the details of a Duster 2x4 access and the 900kg weight of my caravan and the result overall was 81% ability to tow. I would say that's a right result for me, as that is better than I expected for the 1600 petrol engine car. I feel I have made the right choice of model now which is a big relief, as i didn't really want a diesel and I reckon the petrol is better overall for my sort of use which only includes occasional towing. Saying that, only time will tell.