LHR-ABZ - when does check-in open at T2?

I will be travelling with Little Red on Friday to Aberdeen for the first time. When will I be able to check-in my luggage? Many thanks.

Little Red check in at T2 is open all day as there are a total of 9 flights a day to EDI & ABZ.

We flew to ABZ a couple of weeks ago and got to the airport 3 hours before the flight and were fine checking a bag in, but our flight was in the afternoon. Its a shame LR is stopping as I've used it a few times to MAN and Scotland.