Are you operating this TT trailer in the US or Australia. The 240VAC is the normal AC VOLTAGE for their trailers. I suspect you are referering to a JAYCO CARAVAN version TT trailer for use in Australia.
This trailer should have a 12VDC operation using batteries for the times you want to operate it off the power grid. I have never run into a trailer that did not have a 12VDC WATER PUMP. Your 30 AMP Wiring Plan should look something like this except the input AC is 240VAC verses the 120VAC that is used in the US. All of the DC appliances and items should run from 12VDC including your water pump and your ceiling lights etc.. Perhaps all you need is a 12VDC battery hooked up...
I think we are going to need some more info of exactly what you have and are you using this trailer in the US or Austrailia... I'm confused anyway but I am old haha...
Roy Ken