Help, what's gone wrong?

Hi All
Trying to make the best of concreted yard with various potted plants/shrubs. All was going well until last couple of days noticed plants looking a bit on rough side. Maybe we have been over-watering/over-feeding. We have been using Doff slow release fertiliser for all plants. Any help would be appreciated.

 

Looks like caterpillar damage.

 

Thank you for the reply, have you any idea how to prevent this happening. I can't actually see any on the plants.

 

I've found that they hide in the soil sometimes. I've got them out by submersing the pots for half an hour till they come up for air.

It doesn't look like snail damage but check under the rims of the pots just in case

 

What is the last plant in photo 4?

 

Pic one looks like a bad insect attack, pics 2 and 3 look like very minor insect attack and pic 4 looks like some kind of wilt disease.

 

Snail or caterpillar damage.....check at night time to eliminate snails.
Magnesium deficiency too.... see picture 3 Spray with epsom salts to fix