Thanks: both bathrooms have humidistat fans and the kitchen has an extractor too, so the idea if the air bricks is to improve ventilation of the solid (south facing!) wall ...
Does this help?
http://www.diynot.com/network/Damsonjohn/albums/20568/76849
I had to hang out of the window to get this :-)
it shows the exterior surface of the wall (painted!!) that is to the right of the window
there is a conservatory outside that makes it difficult to get a shot that...
Interested in any theories from the experts on here..
This window was installed about 10 years ago, I now have this mysterious horizontal damp patch spreading from he right of the window frame
I think the whole window needs refurbishing on the outside (renew sealant, protective strip etc) but...