A day or two ago a friend introduced me to someone who had recently received an underwriting decision from an insurer. It was a deferral for five years. She told me her story and I thought it was worth referring her to a professional financial adviser. It seemed likely it was worth applying with another insurer (I've got similar medical issues and have always been able to get cover, so there is a good chance she will be able to). The deferral wasn't for all the cover she had applied for. Choosing to take what was offered she accepted the life cover offer without the income protection.
Of course, the first insurer, that issued the deferral, is perfectly entitled to decline any risk that does not fit its commercial model. It doesn't have to tell the applicant that they could get cover elsewhere, even though they probably knew that she could. They weren't giving financial advice, just offering a product.
Equally, when the client gets cover for the income protection, she is likely to take out life cover with the new company too, and cancel the old, because she is perfectly entitled to prefer the convenience of one insurer, and is likely to feel happier with the one that can cover her for income protection as well - rejection by one and acceptance by the other can have an emotional effect. Both those decisions, by the insurer, and by the client, are just the cold, hard, facts of the marketplace.