Hello and welcome to the forum.
You are not supplying enough information to make an informed opinion. For example:
Which engine does your car have?
Is it a manual box or an automatic?
Do you know what the maximum towing limit of your car is? (Check the handbook)
What model caravan are you towing?
Have you towed for many years, or is this all new to you?
It's worth noting the 85% tow weight rule is not a law, it is a guide and a recommendation for drivers new to towing. There is nothing to stop you towing at 100% kerb weight.