My sister-in-law has a possible heart issue, which is waiting to be investigated. Meanwhile, they are due to go on holiday in May (booked some time ago, before the possible heart issue arose) and the existing travel insurance is due for renewal. The company refused to renew, even refused to quote. I think she needs to check the 'small print': if the expiring policy pays out based on when the issue first came to light then she should have a claim against that policy in the event the holiday has to be cancelled; if it's a claims made basis, then she's got a problem which is not easily resolved.