Always plenty of time to get a shower and a drink in the lounge. You will be at one of the C gates so head along the moving walkways, turn left at the duty free shop and take the first escalator around the corner on the left.

In reality you usually only have 45 mins between deplaning and having to line up again, but from F you'll be first off so no issues there.

When coming back from Australia I always adjust my sleep pattern a few days before flying, staying up later and later. Having done that the last couple of times I've had no problems coming back to the UK. In my experience trying to stay awake on a dark plane after eating is a tough exercise if your body has been used to sleeping at that time.

So my advice is have a few late nights out before you leave! It will make all the difference