Tube leak Valiant DR750
I inherited an apparent leak on what appears to be one chamber on my boat when I bought her. I think it is on one particular chamber although this chamber goes down and also the adjacent chambers also sag somewhat. I assume this is due to the chamber ends being flexible. I had hoped this might be the valve and thus a relatively simple repair but I have pumped this chamber up and soapy water tested around the valve and found nothing. I then progressed around the taped joins and all stress points like grab rope securing points and found nothing. Finally I tried the whole section of fabric wondering about a pin hole somewhere but again nada.
I am at a loss as to where to look now and wondered whether I am missing something obvious.
Thanx in advance.