The fact that the picture shows 1288 kg, and other pictures you have posted in #24 show 1488 kg indicate a caravan at Mass in Running Order (1288kg) with a 200kg payload which gives a MTPLM of 1488k, which is very close to your caravans MTPLM of 1500kg. Given the year of your caravan the 1288kg could be its unladen weight. Which is basically an empty caravan, no gas bottles, no battery etc. So your 200kg payload has to account for everything you put into it including gas, battery, mover if fitted etc plus all your othe equipment and personal stuff. Does your label by the door, or owners manual give details. Alternatively around the time of your caravan Mass in Running Order came in. MIRO/MRO fir your size caravan would have included the weight of one 10kg gas cylinder (6kg gas plus 4kg cylinder), electric cable, steps, portable water pump/hose unless internal fitted, documentation and handbooks. So if it’s MRO you have another 200 kg payload, if it’s unladen weight you have less payload.