damp patches

[ToolTimeTinkerer]

I have a few damp issues:

One in the bottom corner, neither of the corner walls are external, the wall that's wet the most is internal solid wall on the other side is the sitting room. The side with less damp on is the bathroom shower wall that has not been used in a long time.

Any advice on what it could be?

Second issue is the window damp which I think is because of a trim missing outside...

 

[DAZB]

Most likely cause of the internal walls would be the pipework to the shower and you may need to check into that. The window issue looks related to the junction of downpipe as it is clearly spilling water shown by the condition of it with mildew etc... it has one bend too many and it also looks open ended so really that should go down to a drain somewhere or it will blow back all over the house. The pointing isn't great either and you could do with replacing the sealant too while you are at it and then refix the trim.

 

[foxhole]

Agree, your down pipe discharge's onto wall and will soak that corner of the property .

 

[ree]

OP,
The backyard wall needs copings, its getting soaked - and where it butts into the house it might possibly be causing penetrating damp into the kitchen walls.
There's damp signs top left inside the window opening.
However, judging by the brick bonding you have cavity walls? How thick are the walls?
There's something odd about the kitchen window lintel? Its hard to see window head details.
The window frame would have been best set back 75mm from the face of the back wall - maybe someone can make a Hood Moulding to shelter the window opening?

Theres a lot of damp too near to the electric outlets - this could be dangerous.
The fused switch is missing the fuse and fuse cover - this also could be dangerous.
Where are the plug wires going to?
Why not post a pic of the inside of the shower tray ?