Welcome to the forums and i hope you will find great pleasure in your gardening.
It's a continual learning process, so there are wins and losses along the way.
First can I say that whichever family member managed to dig up your couple of mature birds of paradise, deserves a medal, because these plants would have to have one of the deepest and toughest root systems! I shifted a baby one once, and it took me a crow-bar and a great deal of sweat!
They are often started by removing suckering new plants, but also division. In either process I suspect there is some damage to the root systems, and that's probably what you are seeing now.
Please don't worry too much, these guys are sooooo tough that they are almost certain to survive. Just, as you say, its not an ideal time of year, as they won't be in growing mode to recover. I'm sure the problem is only initial transplant shock.
Try a couple of doses of seasol, that sometimes helps. Cut off the leaves that are struggling, and as soon as the flowers are past their prime (or do so now - they last well as cut flowers) cut those off, too.
The position and drainage you've chosen sounds fine. If there is any chance that they are actually getting more sun than they were in their previos home (even though the tems are getting wintery, the Qld sun is still quite strong) then you might help them "harden up" to their new position by giving them some temporary shade. This could be a bit of shade cloth or even some unwanted other greenery - shrubby stuff, cut off and stuck in the ground nearby to shade them.
If you have watered them in well at planting time, don't overdo the water from now on, or any damaged roots that are now recovering, may simply rot. Normally they would not get much rain over winter and they are better on the dry side in that season. Also, don't waste fertilizer on them yet, that would do more harm than good.
There's almost no large plant, that will not suffer a little set-back from being completely re-located, we home gardeners usually don't have the equipment or the man=-power to dig up a big enough root-ball to make it that easy. But most plants are also very forgiving, and eager to survive.
I think yours will be fine in time, don't stress if they look much worse before they look better, you may have to wait till spring or summer to see an improvement. New leaves, will be a good sign at that time.
good luck with them.

Hi alison thanks for the welcome and thankyou so much for your in depth reply much appreciated,my bird of pardise came from murwillumbah and they was shaded under a huge gum tree so id say your rite there probally in shock from a totally different enviroment.you say cut the the leave's off the ones that have wilted when you say this do you mean from the top of the leaf stem or at ground level,if at ground level some of them will be a bit hard without damaging others that are attached to the same stem.Do i just cut the flower head off just below the head and will another grow again on the same stem.Sorry for all the questions but i am a total newbie.Thankyou

Hi sjmc
They won't flower from the same stem ever again, so you can cut it as low as you want.
As to the leaves, I'm only usuggesting you remove really damaged looking leaves as they aren't going to recover, and they just use up resources and energy the plant can use in better ways. So, cutting just the leaf stem near the top is fine.
Later, when its established, you can tidy up a bit better, but always trying not to do any harm to good stems.

Just a little side point, I have a seed pod on my bird of paradise, I understand that's not very common. If you are interested to know more about the bird of paradise, use a search engine on how they get pollinatd in their native habitat by nectar-seeking birds. Anyway I think I have to be pretty patient, it will probably take 6 months to ripen!

Here is a link that might be useful: pollination of bird of paradise

Thankyou alison for the reply what i have done is used a peice of bamboo as a splint on two of the leaf stems which had wilted as the leaves are still fine but i will cut the flower heads off as one has stopped flowering know and the other is on its last couple,i will keep you updated in this thread to let you know if they survive this harsh winter.