The Whitburn band, whose debut album WL hit the No.1 spot in April, are among the acts to have performed at the Bramham Park site this weekend, as well as at sister event Reading Festival.
Lead singer Jack Cochrane, whose band are set to play Glasgow's TRNSMT festival in September, heaped praise on the audience for their enthusiasm during their set.
Speaking after their set, he said: “I think we appreciate coming to places like Leeds. There’s a passion and a crowd in a place like Leeds that we thrive off. We feed off that.
“It really encourages us to be at our best and we have been needing that this festival season, so it has been nice.”
Bassist Callum Wilson said: “It definitely felt good just to be back on a main stage again after so long off big stages.
“It was certainly a baptism of fire but it feels like Leeds is always a good place to have that baptism. The crowd give you so much. Everybody gives such so much back and it’s class.”
The quartet wrote a series of letters to First Minister Nicola Sturgeon this summer urging her to introduce further support for musicians and crew in Scotland and also signed an open letter calling for a “clear plan of outcomes and support”.
“We felt a responsibility to be doing that,” he said.
“We were upset and we also felt that it was affecting artists everywhere, being ignored like that by government. Music is such a big part of the culture, especially where we are from.
“That feeling of being ignored was really frustrating. That was a place where we tried to express that through sending letters.
“I think that there has been changes made. In Scotland there is a big tour fund for small venues and stuff like that. If the letters we sent put that stuff in motion or even just in the heads of people, for sure that’s something we would do all over again.”