Angel's wings eaten leaves sorted?

I've been poking around my plant with holey leaves following a discussion posted over the weekend. I've found a caterpillar under the top layer of the leaf which looks like a sawfly larva. They are a pest I seem to have gained since having landscaping done. I don't like using chemicals but am thinking of getting some Bug Clear. What do you think? Sawflies are very secretive beasts and wrap themselves in my rose leaves too. I don't know if the downy leaves on Angel's Wings would be spoiled by spraying or whether spraying would be of any practical use. Any ideas fellow gardeners?