Found the caterpiller or larvae on my lemon tree. Appears to be eating the leaves but have only found one so far. About 25mm long Furry with htree yellow blobs
Vapourer moth, Orgyia antiqua.
The larvae photos there give the impression the pale tufts are straw coloured, whereas often they are a pale lemon yellow, like yours.
(scarce vapourer moth is different)
You'll see from this discussion that they (the larvae) will eat a wide range of trees & shrubs
Beware the hairs. They are there (as with many hairy larvae) partly to deter predators, and in humans they can induce a skin rash.