The fact that a credit check was done will remain on file for five years but nothing to do with what the institution decided on the basis of that check.
Example below is from my CCR request showing a PTSB approach last year.
View attachment 6396
5 years seems a long time to retain this though, for some reason I thought it was only one year.
Not sure why the 5 years is the retention period either to be honest but I don't think it makes much difference. Plenty of people apply for loans and don't take them or apply to multiple providers at the same time if rate shopping, so this footprint shouldn't matter to any lender.
I don't think the ICB even contained data about refusals so not sure where that idea originated.