Investigating a leak.

I have a damp patch on my kitchen wall that I am gradually trying to deal with. Call in the professionals I hear you think. I have had 3 companies look at it and promise a quote. Nothing. One guy said get some of that sealing paint and paint over it and forget it. I don't think people from the companies have any idea where the damp is coming from. Its halfway up the wall- not rising, not coming down. The wall behind it has been repointed and sealed. The gutter above it is sound. Went in the loft today in that heavy rain and no leaks.
Why is there a polar bear in my loft. I'm not sure. It gave me a surprise when I looked at the picture cos there is nothing up there except insulation. You got it it's an insulation bear.