Mike,
Here is the RHS link to the first generation madidum hybrids which I sent to you as an attachment to a PM.
The International Orchid Register / RHS Gardening
Keep in mind that there are now 2nd and even 3rd generation hybrids which will take the madidum traits one step further.
Diversity in a collection is always important in my opinion, so you do not get bored with the same-old-same-old look. With the way you are growing, I would look at other species and their hybrids to round out your collection. You do not need to concentrate on the warmer growing Aussie species and their hybrids.
CL