Someone gave me an excellent method for leak-finding: start with a running hose, on the wall where you have the leak. Start at the lowest point and blast what looks like a potential leak. Then check inside, if not that, then hit the next place up the wall, and continue til you find where the water gets in. You may want to wait a minute or two and do this slowly, to give water time to run through the wall to where it comes out inside. I had endless leaks, really weird places but sorted it out, after going only slightly crazy.
Wherever you go, there you are