Battery Drain on p38 4.0 se

Hi all, I am still getting a drain when my p38 is standing for a day. i have fitted a new battery the bcem is brandnew on the inside so the fixing garage said. i removed the rf reciver but not so that i could use the remote is that were i went wrong unplug it and use the key. any one help

i have just had drain problem it was plug on drivers side down by right foot just resolded it

for got to add its ex police with a landrover splitcharge system i think will take a pic.

so is mine mine was unmarked armed response

could the splitter have died? maybe shorting?

picture of the splitter it has no fuses in it at the moment

I'd be tempted to remove the splitter completely and rewire back to a single battery. If its not the RF receiver, there must be a drain elsewhere due to a short or fault - I'd remove unnecessary compenents like the splitter as they just complicate an already complicated vehicle!!!