https://www.google.com/travel/flight...WRiCMqMFrbUas5
F on AA 777 for DFW-LHR, with J on feeder legs. There is an option for BA A380 on the inbound. Connections aren't great (overnight in DFW or LHR outbound, and LHR inbound). Can't speak to the quality of F on AA or BA, but the price seems very low for F. Bookable through AA.com.