The new UK definition of MIRO for caravans does not include a battery, which is classed as a personal effect. Apparently this is to help maintain the user payload levels that we are used to. An 85 amp hour battery will weigh around 19kg, a 100 amp hour one around 25kg.
MTPLM - Maximum Technical Permissible Laden Mass is the maximum weight at which the caravan or motorhome can legally be taken on the road.
MIRO is the Mass In Running Order and now has to include an allowance for gas and water but not a battery
EHEP - Essential Habitation Equipment Payload. This is the mass of the items required for the safe and proper functioning of the equipment for habitation as defined by the manufacturer.
OEP - Optional equipment payload. This is an amount of weight provided by the manufacturer for factory fitted options (e.g. air conditioning). It does not include any items that might be fitted by the retailer such as a mover. These items will reduce the overall payload available to the user.
PEP - Personal Effects Payload is the mass specified for the items which a user can choose to carry in a caravan and which are not included as essential habitation equipment or optional equipment. In addition to a battery this payload will include items such as an Aquaroll, Wastemaster, crockery, cutlery, bedding, clothing, TV, toilet fluids and so on.