Builders
I understand your anxiety, and you are right to be cautious.
Firstly, McCallum have built quite a few apartment blocks in the Port, surely one or two of the Forum members must own one. Interestingly none have commented.
Secondly, my experience of having work carried out on my apartment when I was not here is that they NEVER do exactly what you want when you want it. Compromise is the key and often the cards are in the hands of builders, who know you just want them to finish so you can get on and enjoy your property.
I guess I would ask any builder for references, and go and speak to those folk who have had them build and see what their experiences were. If you can't get decent references, go somewhere else.
Good luck, I'm sure with common sense, you're going to be fine