Challenger sport 442 floor rot

[Forkhandles]

Hello, looking for a bit of advice on my Challenger sport 442 2014, ive just noticed a small section of rot starting on the rear offside underneath in the corner under the wardrobe/storage, it’s only visible from underneath the van , has anyone else had this.

 

[toad a caravan]

It could be water that's collected from dripping off the awning over the years.Any photos? ,Gary