The only way I can decide is to compare images on Canberra Nature, ALA and iNaturalist and may be Mr Google. We try to put names to the insects I post if possible, not just just insect sp. With lanarium the abdomen, amount of hairs and face looked similar and I thought with the amount of sightings on Canberra Nature, it must be fairly common.
I agree completely that it is desirable to identify insects to species, but if there are a dozen species consistent with the same set of images, I don't see how it helps to make a guess of one name from the dozen. In the present case, if you can say that the bee was 10 mm long and not 7 or 8 mm, I would say it was probably L. lanarium.