Poor Egg Lay

The 2019 egg lay seems to be extremely poor. I'm struggling to find early autumn larvae in Savernake Forest, and think that this will be by far the poorest year in 11 years of dedicating monitoring there (through standardised counts). I've also struggled in Sussex, though some of my favourite trees there have been felled.

Today, in three hours of actual searching on several favourite trees in Savernake, I found precisely none. However, I found May feeding marks and silk pads from a larva I missed finding last Sept when I searched that tree; then I found the remnants of a pupal case about 2m away (of a male) - 

This is only the second time I've found an old pupal case whilst looking for autumn larvae in Savernake, in well over 400 hours of actual searching.  

For the record, larvae are just going into the third instar now, a little late. Here's an L2 larva -