Various small items - breeze block issues

[greg1000]

Morning all,

Have just stripped out a wall lining to be found with this. Looks like damp to me?

We also have a crack by a lintel - should I be concerned about these and what would be the right course of action?

 

[Mrs Ten Names]

Judging by the reveal, that's a single skin wall.
What's on the outside? And how old is it?

 

[greg1000]

Yes single skin , on the outside has been an old stool for an oil tank

 

[greg1000]

age not sure, extension onto the house which was built in 1952. I’m guessing late 70s?

 

[Mrs Ten Names]

That 'stool' will breach your damp course, if one exists. As will that step possibly.
Is that water staining form the window cill on the outside?

From what I can see, once the 'stool' is removed, there shouldn't be any damp, notwithstanding any water staining from the cill, or the step breaching the damp course.
But removal of the 'stool' might leave some damage to the render that'll need attention.
The timber wall inside was to provide insulation and a cavity to prevent damp.