We did PHL-MAN-LHR last year. When we arrived (non-EU passport) the line was LONG and slow (so, it wasn't to our advantage). We were in J and one of the first ones off the plane, but I *think* that the EK flight arrived before us (but not sure). We had a pretty tight connection but did make the MAN-LHR flight (last ones on the plane). Our bag made it to LHR with no problems. It sounds like you have a better connection, so you should be fine.