The French outfit also have cup commitments next week but for London, with their Super League results so bad, the knockout competition is all they have left to play for this season.
Tony Rea's men head to Championship Sheffield next weekend - a banana skin tie if ever there was one - and a seventh successive game without a win will have done little for confidence, although they should take heart from a second-half surge which saw them close to one score having been 30 points behind.
But not even a first start for State of Origin star Jamie Soward could drag them out of their results slump as the Dragons, with a last-eight tie of their own against Hull coming, took the points.
The chimes of Big Ben rang out as London entered the field with Rhodri Lloyd amongst them on his debut, but there was nothing timely about their start to the game as Zeb Taia opened the scoring for the Les Catalans. Back-to-back penalties then gave the home side more field position and the destructive Kevin Larroyer made good use of it, with Thomas Bosc tagging his first goal of the night to move the score out to 10-0.
Despite Soward's best intentions, there was little happening in the London attack and they were turned around again as Morgan Escare finished off a length-of-the-field move started by Taia's offload, with Bosc again converting.
Luke Dorn was then denied a London score, although his failure to do so was accredited to an illegal shoulder charge by the video referee, but the full-back dusted himself down to send Jamie O'Callaghan in at the corner.
The normal order was quickly restored as a London mistake was seized on by Escare who did the rest and, as if things could have been worse for Rea's men, Bosc added the two before touching down himself with seconds of the opening half left. Another Bosc goal edged the interval score to 28-4 and it did not take long for the points to arrive in the second half either.
After Taia was denied by the video referee Scott Dureau nipped in to dot down, with France international Bosc again on the money with the conversion. In stifling conditions the quality was always going to drop and so it proved during a dip around the hour-mark, but that played into London's hands and Mark Bryant flew into a gap off a Ben Fisher pass to score.
Dorn then got in on the act as he snapped up a Soward chip to ground and when Dan Sarginson stormed his way over with 12 minutes left, a comeback of sorts was under way. The wind was taken out of their sails somewhat, though, when Soward was left in a heap with the incident put on report, but when Sarginson found a way through for his second, that was forgotten. The hooter would beat them, however.