OK. I thought the wing pattern was non-conforming and I saw images of similar specimens online which were not identified to species level. But I'm happy to be corrected.
Similar dark spots show on the antennae of P. sera and P. australiana. The photo doesn't look like P. sera, and P. australiana was described on the basis of barcode and dissected genitalia, being indistinguishable from P. xylostella in external experience. I think it ok for us to package these sort of specimens under P. xylostella.