Chillies or Pepper - What's eating leaves

Hi

Unfortunately I am not sure whether its a pepper or chilli plant as when re-potting I forgot to remember what was what! Anyway its a fairly established plant but some of the leaves have been nibbled on. 

I have checked underneath the leaves but cant see any insects/pests.  Its in a polythene greenhouse with tomatoes, cucumbers, etc....

I dont really want to spray with insectiside, it hasnt flowered (if they do??) or produced any fruit yet...

The damage isnt too drastic but wonder if anyone can give me any advice,

Thanks

Andrew