I have three nursery-bought dwarf citrus trees in containers in Perth, Western Australia. Two of the three are showing signs of leaf deformation on new growth (see below photos). The trees are all roughly 1.5 years old, and in all other respects, appear quite healthy. The symptoms have been present for a month or two.

It appears to be in-line with the symptoms of Citrus chlorotic dwarf virus, however geographically it seems unlikely.

I've inspected the affected leaves for signs of insects - nothing out of the ordinary.

Any other ideas what might cause this?

Thanks.