Losing my mind with the wet plaster around window

[OldHouse1920]

We moved into an old 1920’s terrace property . It had a ton of hidden damp issues which we worked hard to resolve properly. EVERYTHING has been completely renewed except for windows and doors which I believe were poorly fitted by the previous owner.
I’m a novice but I believe this because the external door frames aren’t secured in place and the window which is proving a nightmare to get dry had a gaping gap above it to the outside where we have now siliconed.

When we bought the house the windows had plastic strips around on the inside and outside.

The inside ones are no longer there because it’s been re-boarded and plastered (when we had assumed that fixing up some of the pointing above the window and the silicone job has solved it all!).
I had noticed when I removed the internal strips that it was just cavity behind and I wasn’t confident the plasterer should have closed that up completely? But he did.

We have a new roof. No roofing issues visible, nothing in the eaves (no damp which could be travelling down). My partner replaced the pointing in sections where it visibly needed it and yet this happened with last nights storm.

It’s my sons room and he’s not been able to unpack from boxes since we moved almost 6months ago. I feel so terrible for him. Salts have started to soak through the plaster.

Please advise what this might be. There’s a little damp to the top corner of the other side also.

We’ve had various suggestions to no avail.
Second floor window.
Guttering is perfect. No issues

 

[opps]

Sorry, it doesn't help you but the images are really low resolution.

I can't tell if they are condensation or ingress.

 

[OldHouse1920]

Sorry, it doesn't help you but the images are really low resolution.

I can't tell if they are condensation or ingress.

Thanks - it helps because I wouldn’t have realised . Will add new ones