After the cruise they flew to London to meet Lafleur's daughter. The fit and active grandmother, who trains dogs and plays badminton and table tennis in the Hibiscus Coast, still had a dry cough so they insisted she go to a free National Health Service (NHS) doctor.
Dunn, who Lafleur says only visits the doctor every two years for a medical to get her driver's licence and had no pre-existing medical conditions, had dangerously high blood pressure and her legs were also extremely swollen.
She was referred to St George's Hospital in Tooting, South London, where she was diagnosed with a chest infection and sent her away with antibiotics.
The public hospital was too busy to write a letter to Dunn's insurance company Cover-More so Lafleur paid £85 ($155) so a private GP could. While he was examining her, Dunn's blood pressure was still high, Lafleur says.
Private cardiologist Dr Jonathan Hill at London Bridge Hospital saw her the next day and said she had acute heart failure, Lafleur said.
"Something had happened on her trip. It could have been the stress of the trip or the infection she got half way through the trip ... It had triggered something to cause one of her heart valves to malfunction and her heart wasn't beating or ticking properly and fluid was building up in her lungs," Lafleur said.
Lafleur said she kept calling Cover-More to see how they could help, but felt she was met with delay tactics.
She says she was told they would not cover Dunn in the UK since she could be treated by the public hospital despite being misdiagnosed and speaking with Dr Hill.
Lafleur says she dug into a $45,000 bank loan she and her husband had drawn for home improvements and paid £15,000 for the four hospital night stay, plus £15,000 for tests and consultants.
When they missed their flight back to New Zealand last Sunday because Dunn was still in hospital, Lafleur says she called Cover-More to see if they would step up.
She was told Cover-More would not approve the claim until they had received confirmation from Dunn's doctor that she had no pre-existing medical conditions. Four days later still had not heard and was also told by her mum's doctor that he had received no communication from them, she says.
Lafleur said she was sick of shelling out about £125 a night on a hotel so last Friday booked two one-way business flights costing £7000 because the doctor had recommended her mum lie flat.
Lafleur said she wanted their experience to serve as a warning for others as she paid $1400 for her mum's travel insurance and $465 for hers.
"It really bothers me ... what if we hadn't had access to our home improvement account? What if we didn't have a cellphone and she was on her own as she doesn't use a cellphone?"
Cover-More New Zealand chief executive Bruce Morrison told the Herald they would normally respond much sooner, but there had been some confusion over names when requesting Dunn's medical notes.
"The delay from the whole start has been around Christine using two christian names. Her actual name on the policy is Doris. The GP didn't recognise her by Doris, but that's her proper name on the policy document and that's what we asked for."
Cover-More received the notes yesterday afternoon and Morrison said they would contact Lafleur about what they were entitled to.
Under the policy, people were expected to go to the public hospital unless it was deemed medically necessary.
"I can see from the notes that she didn't have a great time with the NHS system over there and I think she lost a little a little bit of faith...
"We need to work out from her what led her to go private and we will look to treat this fairly because it did not look like she was getting the treatment she was after."
