@Smowball
As the NHS article says, the reasons why the 1 in 4 who get two copies of the variant gene have only 10% risk of symptoms are unknown at this time. I've studied biochemistry and know the absorption and processing of iron in the body involves dozens of molecular structures which we all possess but whise performance varies between individuals, for reasons also down to genetics.
Nothing wrong with being a 'carrier' and the variant gene will continue to exist until science gains the powers to repair it. But first they'd probably want to research that 'unknown' stuff so they will need carriers and sufferers for generations to come. Most of their insights into our own molecular inner workings stem from studying rare disease conditions.
A lengthy preamble to recommending that you alert your children to the risks of the condition but the decision to take a blood test is their choice. It may be a mild imposition on their respective future partners to also go through a blood test. Years down the line they may find themselves obliged to declare it, for insurance purposes or divulge it to a subsequent partner, even if negative.
If there's a right 'etiquette' for this sort of thing, I am ignorant of it.