I've had mixed experience with this previously when I was doing AMS - LHR - HKG. I was on the BA 441 (7pm) departure and came to AMS at 10am since I had a meeting near the airport at 12pm. They stated that they couldn't check in my bag due and had to come back 3 hours prior.

Also had the same experience doing an ex-EU run and had an 8pm flight back from DUB - LHR.