Misdiagnosed on travel insurance

[StuntNun]

My 78-year-old DM has booked a trip to Canada to visit relatives and has arranged travel insurance at a cost of £1500. Afterwards, she realised that she had not disclosed that she had had a coronary calcium scan that showed mild calcification. She phoned up the insurance company to tell them about this and the clerk decided to put it down as cardiac ischaemia and asked for another £900 for the insurance. My DM said that she doesn't have cardiac ischaemia and provided a letter from her GP specifically stating that she does not have it. The insurance company's position is that they are not medical experts therefore they cannot review a GP letter and remove the cardiac ischaemia from her medical insurance. They have said that she has to either pay the extra £900 or they will cancel her policy. They have also told her that they communicate with other insurance companies so other companies will be expecting my DM to disclose cardiac ischaemia if she tries to get a policy with a different provider. She's been back and forth with them on the phone and they're saying there's nothing they can do. Has anyone ever had a similar problem, and how did you resolve it? She's considering paying the £900 but she's worried how it will affect future travel insurance costs as she will have to pay a premium for this medical condition that she doesn't even have.

That’s odd. Every time I’ve contacted my travel insurers to disclose changes in medical info, they're sent me a follow up letter to confirm everything I’ve disclosed and the letter tells me to contact them again if theres any mistakes.
In addition, the phone call will have been recorded so they should be able to listen back to the recording to confirm what your DM has told them.

Having just read up, I can see that calcification is a build up of plaque, and that causes cardiac ischaemia. Maybe thats what the insurers are referring to?

Start with a SAR (subject access request) from the insurance company to find out exactly what is in their records. Then it should be possible under GDPR to require a correction.

I suspect this is it.
I have had experience where I declare a type of arrythmia and they alter it to another. I imagine the premium is the same either way.
Try ringing for her. She'll need to be present to give consent, ask to make a formal complaint. They should put someone more senior on. The call handlers have zero discretion but a manager should at least listen to you, listen back to the recording and get an explanation from the underwriters.

Another suggestion would be for you to get an online quote from a different insurer. Use fake details and see if they also change calcification to ischemia.

She has mild calcification which means she is at low risk of cardiac ischaemia.

She's decided to cancel the policy and try again with another company. They agreed to remove the ischaemia but only if they could change it to atherosclerosis, which she is also not diagnosed with. Considering that she has a number of disclosed conditions and is already paying £1,500 for insurance for a single holiday, I can't understand they they're so desperate to wring even more money out of her for medical conditions that she doesn't have. She'll only get a partial refund but that still leaves the insurance company with less money than they would have got from her.

Medical insurance makes no sense. I'm on a number of medications which mean things like my cholesterol levels and blood pressure are better than most people but I still need to pay nearly a grand for annual insurance.