The Broncos won just five of 27 games in Super League XVIII and they have lost all six of their matches so far this term.
Their latest defeat came last night when McDermott's Leeds ran in 10 tries in a 54-6 romp at Headingley.
Despite his side's comfortable margin of victory, McDermott says that he was impressed by London.
"I didn't think we ran though London with ease. I thought they were dogged throughout," McDermott told reporters.
"We were too fast maybe in the outside backs, but I don't think physically we blew them off the park and credit to London for that. They gave us a bit of a test.
"They will get somebody this year. They troubled us with some of their plays. We were so focused because we didn't want to be the first team to get beat by them. I think they'll go on a bit of a run this year."
Leeds are currently top of the table.