I leave the pool area, thrust the card in his hand and tell him to scram. Sighing, I retreat to the thermal suite to detoxify and am luxuriating in the warmth of the heated tiled loungers, positioned to take advantage of the panoramic window looking out on the calming sea, when I realise the card I gave him is a spa key-card.
Bliss interrupted, I leap off the lounger and dash into the changing room, only to find my locker key doesn't work. Curiously the locker seems to be in the wrong place. Embarrassment sets in as I realise I am in the men's changing room. Panic follows when I try to leave, select the wrong door and bump into a urinal.
A detoxifying experience indeed.
I finally make it out, retrieve my other half and we stroll around the promenade deck of the mid-sized ship, which has recently been renovated and is on a 92-night world cruise from Southampton.
It's more than a spit-and-polish renovation. This beauty is in ship-shape after a multimillion-dollar refurbishment that includes the addition of 24 cabins, including six single cabins - a first for P&O. The beds are incredibly comfortable and it's so serene on this adults-only cruise - usually I'm woken early in the morning by the screaming spawn of Chucky who lives next door.
Up to 3000 people, including crew, are on board on any one leg, including a number of P&O Moaners, one witty Pom reveals. It can't be too bad, though, because a number of Brits have told me they do the full cruise every year to escape England's grey winter.
As a cruise virgin, I'm in a small minority. Almost everyone I talk to has been cruising before. Okay, they are almost all older than me and at times cruising is like watching the television show Benidorm on water - there are numerous crispy, brown bodies on the sundecks - but we fall in love with this effortless way to travel, without the pressures of having to move hotels and catch planes and trains between destinations.
At Queens Wharf in Auckland, we were through Customs and on board in less than five minutes. Our bags were deposited in our rooms soon after and we dodged only a few frisky oldies on mobility scooters while getting our bearings.
Cruising is an extremely safe way to travel. We are sampling the Auckland-to-Sydney leg, where there is no trouble during our three-and-a-half days at sea, but from Dubai to Egypt armed guards are picked up to boost security, Captain Aseem Hashmi says.
"But they won't open fire unless I say so."
There are pirate drills for passengers, but looters are unlikely to board this beast.
"The passengers would be of more harm to the pirates with their handbags, stilettos and scooters," the captain says.
At 4am, after our first night on board, it is our ship that is trying not to harm fishing boats lost in the fog. Later, on a visit to the bridge, master and commander Hashmi (who turned down a role as a cook in Captain Phillips - he thought he should at least have been offered second or third officer) tells us the ship zig-zagged around them while sounding the horn at regular intervals until the danger had passed.
In a fog more officers are required on the bridge, but when the ship is on auto-pilot a tiny joystick is all it takes to control it - one click to the right or left equals one degree and the ship sails at a consistent speed of about 17.8 knots (full speed is 22 knots).
Leaving the bridge in good hands, we forage for food, an easy task on a boat that has five restaurants - each with its own galley - as well as bars and cafes. Belvedere is a buffet-style restaurant that occupies a huge area of one deck and is open almost 24/7. You can also order free room service at any time of the day.
Along with the renovations aboard Arcadia, Michelin-star celebrity chef Atul Kochhar's Asian-fusion restaurant, East, has been introduced. But my favourite is Marco Pierre White's Ocean Grill, where succulent lobster with garlic butter and bearnaise sauce tempts me on two consecutive nights.
As well as picking up 200 passengers in Auckland, 110 tonnes of fruit and vegetables were hauled on board. Then there's the local beer and wine.
Most nights we let our dinner settle while we enjoy the evening show in the plush, three-tiered Palladium, which seats 700.
My husband is excited to find Pam Ayres is performing one night - as are others, as there are no seats for us at the 8.30pm show. We manage to outrun a few oldies to the second session at 10.30pm, where we listen to Pam reminisce about her teenage years in a tiny village and her desire to be caught in a passionate embrace.
The following day, when our host organises a chat with the poetic comedian - who is promoting a new book You Made Me Late Again!, a direct quote from her husband - I relent and let mine tag along. He decides to fulfil Pam's teenage wishes after being granted a photo with her.
"You can be as frisky as you like," she says, and he clings on like a limpet.
For the rest of the cruise I urge him to behave and lay low. The only thing I require of him is to set the alarm on the morning we arrive in Sydney so we can see the ship's entry into the harbour around 5am and watch the captain's "controlled collision with the dock".
"You have to think 20 seconds ahead because that is the reaction time of the ship," says Hashmi.
"It's like turning a double-decker bus - the power has to be just right. We don't look at the controls, we look out the window. The passengers who are watching us dock think I'm looking at them and they are madly waving at me."
My husband wakes me and I'm dressed and halfway out the door when he twigs that he's set the alarm two hours too early.
"Oops, come back to bed, honey," he says apologetically.
There's a good reason they added those single cabins.
CHECKLIST
All aboard: Fares for 2015
Arcadia's 20-night voyage from San Francisco to Sydney departs on January 31, from $2919 a person twin share. The full 106-night world voyage departs from Southampton on January 6, from $16,859 each, twin share.
Arcadia's sister ship Aurora will visit Tauranga, Auckland and the Bay of Islands next year on her 105-night South America and Pacific Adventure, with fares from $4459 each for a 33-night sector from Auckland to San Francisco, departing February 26.
