UKPassats

I have boost leak somewhere on my tdi 130 avf. You can hear it blowing out on boost. Initially i thought i had found it as the was a big soot build up around the top intercooler pipe where it goes into the intercooler. I replaced the seals and its no different. I have taken all pipes of across top section of the intercooler and checked them. Before i start checking and lower ones has anyone experienced the same?

Thanks in advance