Last night, we were glued to David Attenborough’s second series, Planet Earth II. The cinematography was exquisite: capturing an opera of nature.

In one of his previous series, David visited the Great Barrier Reef, a stretch of coral clusters, 1400 miles long, a few miles off the coast of Queensland.

When the children were in their late teens, we went to Heron Island, which is one of David’s favourites. It is a coral cay, made up of sand and coral, covered with lush, tropical vegetation. The sea is swarming with effervescent fish, like in Finding Nemo, and the island is littered with thousands of migratory birds. Their noise is deafening. They mate all day and night – with sound effects!

The island, encircled with white virgin sand, is only 800 metres long and narrow, so you can walk around it quickly. It is a jewel.

The accommodation is basic: wooden huts. You eat in a communal restaurant, which is wire-screened, so that the birds can’t steal your food.

The coral reef, encircling the island, has lots of stunning fish, but it also teeming with manta rays and reef sharks. I found them frightening, but Hugo didn’t have an ounce of fear and swam up to them. The turtles were majestic, but scarce.

It looked like paradise, but it was not paradise. Let me explain.

Let’s start with the catamaran trip out to the island. We were told that the sea was rough; sea sickness pills had been recommended. We set off from a calm bay. Next minute, we were in large swell, facing 15 to 20 feet waves. I was facing the back of the boat, so I couldn’t see how large they were up ahead. But every few seconds, we lifted off becoming airborne, and then we crashed back down, over and over again, for an eternal two hours, until we were finally there.

Geoff was facing the front of the boat and could see the gigantic waves. I asked how big they were, as I white-knuckle gripped the table in front. He just put his hand up towards my face, as if to say, “Shut up.” I didn’t mutter another word. Just whimpered, pitifully.

After a while, almost all the passengers were throwing up. Somehow, we miraculously didn’t. I can tell you, it is true, that if someone is seasick they go green.

It felt like the boat was going to break in half.

When we disembarked at the island, I heard one passenger about to travel back to the mainland say, “It can’t be that bad. They look happy.” We were just euphoric to have survived. A number of passengers booked a helicopter return right there on the spot, before they had even checked in.

Highlight – watching the green turtles hatch and crawl to the beach to swim away. Ruined, because most of them were pecked off by hungry seagulls, and so few made it. It made me cry.

Highlight – snorkelling around the island. Ruined, as I told Geoff, and the children, to look at the black rocks, in the shallows, at low tide. Only they weren’t rocks. They were manta rays sunning themselves. I started yelling to leave them alone, as their sting can be fatal. As if they could hear – they were underwater. I was waving my arms around like a mad woman, just like a steward pointing to the exit doors on a plane. People on the beach were staring. Who was that crazy woman?

Thankfully, Geoff and the children realised what they were, when they started moving, like UFOs, vertically upwards from being, partially, buried in the sand.

I was never so glad to be off an island paradise. Thankfully, the boat trip back was calm.