Advice on purchasing first caravan

Hi All,

This is my first ever post so I'm sorry if it is in the wrong place. I'm hoping to buy my first ever caravan this winter/spring and I'm a bit of a novice to it all so I was wondering if any one had any advice. 

I can only afford around £3000-5000 so I'm buying second hand, I am also only allowed to tow maximum 3500kg because I dont have an B&E license and my car is 2170kg gross vehicle weight.

Does anyone have any advice on the best place to purchase a caravan, am I better off buying privately or from a trade dealer? Are there any websites I should avoid when looking for caravans for sale?

Also does anyone have an idea of what weight van I can get, can I push it to the max and get one at around 1300kg or am I better off trying to get a lightweight model at around 1200kg or less?

Finally if anyone has advice on models that would be greatly appreciated as it would really help the search!

Thank you for any advice you have.

Laura