Bay window crack and uneven floors

[CatTrap]

A house I’m looking to buy has horizontal across across the bay window at the bottom.

However when inside the property when you walk towards both bay windows on both the ground and upper level floor you can feel the floor is uneven and slopes downwards.

Pic added of cracks, one side has had a feeble attempt at covering up.

Unsure if this could be something fairly straight forward to fix or if i should move on. I’m leaning towards it not being worth paying a surveyor for just to be told it’s not worth the fix.

Nb whilst the top floor does have some unevenness, I can’t see any evidence of any cracks to the render up there.

 

[Wayners]

Many years ago drainage was put in old houses under bay to make a bathroom in the property and there were no compacting equipment at the time.
Bays sank a bit.
Maybe that?

 

[CatTrap]

I’m adding another picture, this is the top front and bottom front rooms where you can clearly see the dip. You can see the centre is more compacted in the bedroom pic.

Is this likely the joists not being fully supported in the bay window area or are the windows bringing the front of the house down?

 

[CatTrap]

Many years ago drainage was put in old houses under bay to make a bathroom in the property and there were no compacting equipment at the time.
Bays sank a bit.
Maybe that?

Not sure by the bathroom on the ground floor is at the back, where are the problems seem to be at the front.

I’ve added a pic of the front top room.