Hiya,
I've applied and gotten a copy of my ICB a good few months ago. I had a car loan about 4 years ago and after an accident I missed a payment, which I paid back a month later once I realized. I was really worried it would show on my ICB report, but fortunately as I paid it back so quickly there was no mark at all applied. Clean report
I cant say for certain for the example you've given as its a longer stretch of time with missed payments and they have yet to be paid back, but I do know if there is a strike on the report it remains for 5 years from the time the loan is repaid.
If I were you, I would request a copy of my ICB report. You can do it online, and it only costs 6 euros.