Caterpillar

Found the caterpillar on the house wall.  It's the larva of the grey dagger moth (Acronicta psi). The food plants include apple, hawthorn and acer, so it will be OK in our garden.  The extra is a tiny spider, hiding in the wall near to the caterpillar.  The ID app says it is Drapetisca socialis, sometimes called the invisible spider - this was a puzzle, but now I see that it applies to the web.