Aussie gold is not actually potting soil, its a coconut based mix. If its been in the mix for a year now then its likey due for a repotting anyways. Orchids left to long in a broken down media can rot even with careful waterings - it holds on to, too much moisture.
As Ted says, With the new growth comming its a good time to repot.
If you find the aussie gold to tricky then go ahead and change out to something new, as a hobbyist I think we should try just about anything & everything.
For years I grew my catts out in a bark - sphag combo. Now, I use a peatmoss based mixture for everything. It all depends on the conditions and you're water habits.
Don't be afraid to try new things, keep you're mind open.
Maree, You're catt is beautiful, I love that color!!
Good luck with the repottting ~ Happy growing