I have 2 clematis Armondii one that's well established and growing like
wildfire and the other which is not so established and the new growth
is being eaten away by something.

Leafs are gone and the stalk are also gone down little stumps in many
places

As I'm trying to be Organic is there anything I can do to stop this ?
What is likely to be doing this , slugs ?, snail ?, caterpillers ?

Do I need to go out at night with a torch and catch the little B****rs
that are doing this ?