The Exiles opened the scoring through Scott Conroy and Sean Hickey, but found themselves five adrift when Byrne and McEneaney struck four minutes apart to make it 2-2 to 0-3.
With London set up quite defensively by Kerry native Ciaran Deely, an upset never really looked likely after that, although the visitors did cut Louth’s lead to three points twice in the second period.
Colin Kelly’s side eventually snuffed out the threat of an upset in the final quarter, but they were flattered by the margin of victory.
D Byrne 1-3, J McEneaney (2f) 1-3 each, J Stewart, D McMahon, R Moore 0-1 each.
L Mulvey 0-3 (1f), S Hickey, A Moyles 0-2 each, D Ryan, S Conroy 0-1 each.
C Lynch; P Rath, P Reilly K Toner; D Maguire, D McMahon, E Lafferty; T Durnin, J Califf; D Byrne, J Stewart, A Reid; C McKeever, J McEneaney, C Grimes.
G McSorley for Durnin (12), R Moore for Califf (59), J Bingham for Rath (62), R Holcroft for Byrne (68).
G McEvoy; P Butler, D McGreevey, D Quinn; C Carty, D Ryan, C Dunne; J Moran, L Mulvey; A Mpoyles, S O’Grady, A Hanlon; S Hickey, S Conroy, P O’Hara.
A Dunne for Quinn (50), J Lynch for S Conroy (50), S Buckley for C Dunne (60), C Healy for Hickey (66).
P Faloon (Down).