Damp patches outside wall

jessmist

Hi,
I have some damp looking patches on the back of our house outside wall.
Last summer I had a roofer check our roof which he repaired a couple of things. But the roof is only about 6 years old.
The bricks dried out over the summer. We hadn't seen any damp patches on the outside until we had that really cold spell in December. Then when the weather turned milder the damp looking areas appeared again.
We have Cavity wall insulation and I'm thinking could it be areas that haven't got the cavity insulation that are making the bricks look damp on the outside. We have no damp areas inside the house, but the height is upstairs floor area.
My son has removed the kitchen extractor vent and says there is no insulation when he put his hand inside the cavity.
If it is the cavity how do I need to contact to get it checked ? 
The company who installed it has gone out of business.
I have attached a couple of photos.
Thanks o

stuart45

Quite an unusual brick size. Damp patches on the external skin aren't as bad as on the inner skin.

jessmist

Any idea how I get the cavity wall insulation checked ?

stuart45

Can be done with thermal imaging camera, and also a camera into the cavity where it's suspected there's a void.