What's nibbling my clematis?

My clematis is budding up well and I had been looking forward to a good display, but today I've noticed the following. The plant itself seems healthy, no sign of damage to the leaves at all. Any ideas?? I don't want to lose the blooms before they even happen!

 

First thought is earwigs 2nd-bassoon. An insecticidal spray or a trap of tissue paper, straw etc.stuffed in an upturned flower pot. Try it and see if there are any there

 

Thanks @Verdun, I'll give that a shot!

 

Don't discount slugs and snails...