Yes, it was pretty formal although I thought it was 5 or 6 nights. It was a small slice of a QM2 world cruise, which I think would be still a bit more stiff than an Aussie based cruise on QE.
I feel the same as many of the earlier comments Bazza. It was nice to do, but just a bit OTT for a summer cruise holiday. Packing a suit or tux to take on a cruise is very much in the past for me except for a special occasion. All the same, shirt, trousers & tie are easy. As far as formality on QE goes, you can be comfortable with whatever dress standard you prefer.