Water leak underneath the building

Hi Guys, I am moving into a property that has got couple of water leaks underneath as shown in the attached property inspection reports. I am not sure where this leak is coming from, it could be right underneath bathroom or from elsewhere due to substandard waterproofing. The actual bathroom is in very good condition though as per 3rd photo. Please see the attached reports and offer quotations, I can organize a site visit if needed to get the exact scope of work and final quotation. Thanks,