How early can I leave my luggage at the BA luggage drop-off desk?

If I check in online (say 12 hours before my flight), can I drop off my luggage at the BA drop-off desk at any time after doing so? I'm staying at an airport hotel and would like to get rid of my luggage the night before the morning flight. The BA website says to "go directly to the drop-off desk after checking in online" but does not specify if the time limit for this is the same as for the online check-in itself. Are there any BAA employees/seasoned travellers who could advise me?