I thought I'd give you an update on this now that I can get back to it.
We were a bit early for swimming today so DS was helping me and he was most disappointed that it didn't have caterpillars on it, so I have promised to add a row of caterpillars. I think the green of the flower stems will make nice caterpillars, and they could fit under the butterflies further down. My only reservation is if I've got enough fabric. It should be right if I've centred it correctly and if I don't do them any bigger than the ladybugs. Then I'll have to find another speciality stitch to add in too to make it all the same.
The other option would be to replace one of the existing rows - but I can't choose which one I'd want to go, so I think I'll stick with adding one in.
I think I may have also promised to get a little caterpillar button - there will be a ladybug and a butterfly either side of the words, and DS was very enthusiastic about the idea of a caterpillar button. So first I have to find out if I can get a matching one, and then I'll have to figure out where to put it. Maybe in the middle of the row of caterpillars - although that will look rather out of place compared to the rest. Oh well, I'll see.