No, your booking is only valid for the type of vehicle (category) you have selected, which does not include any kind of trailer or object which heigh may modify the factory's heigh by default and which does not occupy more than one place (trailers).
You must check the dimensions of the vehicles allowed in the car park and the maximum height allowed before making your reservation.
Related article: Why my car does not feet into the car park?
If you do not take this information into account, on your arrival, the car park will have to bill your trailer as another vehicle but at the public sale prices of the same parking or refuse the access with no refund.
Luggage or vehicle racks must be disassembled and stored at home as the car parks do not have rooms for this purpose.