Actually, no.
Historical records are scattered on different IT systems and if you go back long enough paper files.
It would be an administrative nightmare to try to allow people to access unused allowances from 1992 or whenever.
Oh Well, unless they embarked on some grand unifying digitisation project, I guess that's the end of that! Given most careers span 45 years, maybe this could be rolled out approaching 1992 + 45 years = 2037. If they have 1980s records on some antique IT system maybe they could bring that forward significantly but otherwise I guess it would have to depend on something more straightforward...