Hi,
I can't say I have heard the 'different gearstick' is why it wont go into reverse.
It can be as simple as the cover plate on the bottom of the remote change is upside down or has been spun around the wrong way that is blocking reverse selection. There is also the reverse light switch which goes into the side of the remote change that if it has been screwed in too far will stop reverse from being selected. Both easy things to climb under the car and check, remove the plate and/or remove the reverse light switch and see what happens.
You should be able to see the gallery now as you have the right access.
If it does turn out to be the wrong stick, then
www.minisplus.com.au are just up the road from you and they would have some second hand one I think.
Terry