Your top pic is a( Edit) a type of asparagus fern. Like all ferns they love humidity. Place a shallow dish of pebbles and water below it might help add to the humidity around the plant as well as misting. You can trim off the yellowing parts but best to take care of the issue as well.
I am not familiar with summers in the UK but the bottom plant does look like sunburn to me at first. But that the damaged leaves seem to belong to one branch so maybe something else? Have you fertilized recently? Maybe someone else will chime in here.
