The bird has been identified as a Willy Wag Tail. We found another baby on the lawn about 30 mins later so now I have two of them.
I tried looking for the nest this morning - no luck
Off to the Vets so they can turn them over to a carer.
Just an update:
Sadly we lost one of the birds BUT the good news is, the remaining bird "flew the coop" today. I put him outside in his cage this morning and when I checked on him, he was hoping around my backyard with his mother closely watching him from the fence. Very pleased to see how far he's come.
It wont be long now till he flies away