Swift Moths love the cold, wet weather

I have some difficulty in identifying these Swift Moths which have been coming to my front porch in the last week, of cool, wet weather. Any help in identifying these Moths would be appreciated. You can see in this image that there is considerable variation in size and colour markings of these moths, yet I assume they are the same species.
I was originally inclined towards the species known as Abantiades hyalinatus (HEPIALIDAE) until I saw the images on Donald Hobern's Flickr Gallery of moths, which clearly showed a violet colour to the hindwings and the upper part of the body. Also his specimens were recorded in January.

My specimens show a deep russet colour, but not purple
on the hind wings, and the body brown.
This was taken at 1/500th of a second, but still the image is blurred
showing how fast these Moths flap.

However, there is another likely candidate: Elhamma australasiae (HEPIALIDAE) . Don Herbison -Evans' encyclopaedic website on Australian Moths says: "The earliest adults appear in January, but they are most common in March and usually disappear by April."
As these moths have just appeared in Robertson, in the last week, when it has been cold and wet, the timing of Elhamma australasiae, as reported, hardly fits. I have written about these Moths previously, on 2 June 2008 (when it was cold and wet); and before that, on 27 May 2008
So, perhaps it is Oxycanus dirempta (HEPIALIDAE). At least Donald Hobern's images of this species are all recorded in May.
What troubles me is the variability of these moths - not just in my images, but in the available images on other galleries and websites.

Here is a handsomely marked specimen,
with a clear wing stripe.
Long antennae are also evident.

Here is a much redder specimen
with spots on the wings, not the clear wing flash

And a really dark specimen
with wing blotches, not white spots nor wing flash

Here is a very pale specimen, viewed "head on". It does look very similar to this specimen of Donald's Elhamma australasiae, so I am totally confused.I took this image and marked eight different moths
around my front porch at the one time.

I must admit to an assumption that these are all the same species - simply based upon the similarity of habit and timing of their appearance.
As I said at the beginning, any help in identifying these Moths would be appreciated.

Edit:

Donald Hobern came through with an ID - many thanks.
He said they "all look good for Oxycanus dirempta".
That's great.
Thanks Donald

Denis