Sorry this one isn't the case moth. This is possibly the caterpillar that skeletonises apple tree leaves. It looks different to photos taken the other day so may not be the same. Or may just have progressed. It is certainly slightly larger. Hopefully there is enough detail to identify it.
That's what I figured. Interesting though that the earlier instar was a skeletonising caterpillar. The current one is just chomping on the whole leaf. And will its next incarnation eat the apples? And yes I find behaviour and physiology more interesting than taxonomy. But you need to know what you are looking at as well as what it is doing.