Originally Posted by Globaliser

Then it's entirely your option whether to collect the bags at LHR or to through-check them to JFK. The bags can be through-checked so long as the connection time is no more than 24 hours.

Your departure will be scheduled for 1150, unless it's scheduled for 1145 or earlier or 1155 or later! At LHR (and for that matter at most places I go to), scheduled times are always at multiples of 5 minutes.