Hello Michael,
You have fallen foul of the propaganda about 85%. It is not a rule, and it has no legal significance at all, however, whilst you are not obliged to conform to it, the underlying principal of keeping the caravan as light as possible does make good sense.
It is doubtful that the difference between 85 and 87% would be noticeable, so you probably will get away with it.
I feel I should remind you that the on line web sites that off outfit matching have been shown to contain errors, so you should check the figures yourself. Obtain the weight information about your car an caravan from the vehicle registration documents you have.
The other thing you should be aware of,is that simply getting a favourable towing ratio does not guarantee a good tow. Other factors have just as much impact on the dynamics of the outfit, so it is important to get the loading inside each of the vehicles to get the correct nose load. The condition of the vehicles mechanics and tyres,and not forgetting the one element that can have the greatest effect and that is the driving style.