Regularly get/read back landing clearance @ LHR with the 30'-50' Rad Alt calls in the background.
There is no general rule as the military have... LVPs has a rule, and in general some appreciation of "why" the clearance is late is needed e.g. departing aircraft on the threshold has different considerations (bmi 321 v BA 744) to controller awaiting taking off aircraft getting wheels off, or preceding landing clearing the runway.