FTR: I don't have any 'series' as the term is commonly understood around here. So I don't have the problem.
@Jellby - would it help if MDE displayed series_sort() - non editable?
@chaley - I'd noticed the sort column in the series table definition previously, so I was a bit surprised to find today that it wasn't in Manage Series. Not like you to overlook something like that - now I know why
BR