Thats so familiar on an Elddis Xplore,The leak is the RH awning rail/roof/front panel joint , where the sealant has failed (or been badly applied). it runs all the way down the inside of the outer skin to the front window, as well as showing in the top of the cupboards.Photos of an Elddis a friend did not that long ago. It's time consuming but straightforward if you take a methodical/unhurried approach.