They toured relentlessly for the next few years, barely stopping the tour bus to make 2012's Babel. But with Wilder Mind they took time off and returned to the studio fully refreshed. And what was remarkable, says Lovett, is that they all found themselves at the same point musically.
"We spent a few months apart, which we hadn't done for about six or seven years. When we came back together to play each other some songs, it was like we had naturally written this way."
Lovett believes that shared vision came from an ability to not get too self-consumed, particularly with the perception of what, or who, the band was. Although he admits, it's become apparent in the past few weeks just how strongly people feel about the difference in sound.
"The perception was a lot stronger than we'd realised, particularly when it came to the banjo. We hadn't realised how firmly people had attached us to an instrument. But that's all the more reason for us to have done what we did with this record. No one wants to be put in a box and tied up with a bow."
The first sign that Mumford & Sons was on a new musical path came with the release of the album's first single, Believe. It drew comparisons to Coldplay and caused a stir on social media. Tweets such as "Just listened to the new Mumford and Sons song ... it's a joke, right?" and "One of Mumford's sons is Chris Martin, apparently" summed up the
world of confusion.
Some of that fear should have subsided by now since the album's release.
Yes, this is a different sounding band six years on from its debut, but Marcus Mumford's distinctive vocals are the common thread, as is that sense of live energy the four-piece has managed to capture in the studio.
Songs like The Wolf, the title track and Just Smoke rollick along and, when you need to catch your breath, there are quieter moments in Monster and Only Love.
"Perhaps people will judge it on a single or two and won't want to dig any deeper. But I think it is consistent. We've always written autobiographically, there's consistency in the style of writing.
"The instrumentation may have changed a bit but the approach to stories is similar. It's just that the stories have changed and now we're reflecting on life in 2013 to 2015, instead of 2005 to 2007 or 2009 to 2011. It's the next phase," says Lovett.
The process of making Wilder Mind also differed from the first two albums. "With those we were very much trying to record what we were already doing live. This album is slightly different in the sense that we had never played any of the songs before.
"After doing the demos and working out what the song was, when we sat down and made the record properly, we'd only played the songs five times, some of them even less.
"There was an element of freshness and naivety to the music itself and it has this energy of newness as a result. And we recorded it live in a room to tape, which was a new process we hadn't done before," he explains.
Lovett describes Mumford & Son's songs as "snapshots" and their records as "family photo albums". He loves that one day he will be able to look back on those with the knowledge that the band didn't just sit still.
"We didn't try to write songs that stuck us in one phase of our lives. This record has meant we look forward. It has given us the assurance we can continue to be relevant to ourselves, that we can stay present and that energy comes from a rekindled youth behind the music-making process."
From here, the foursome has at least a few years of touring ahead of them. It is hard work but the band is approaching this next leg of the journey with a new spring in its step.
"It's an opt-in thing. We don't have to do this. There is no ball and chain, no one is cracking the whip. We choose to be in this band and we choose to make music.
"And I think we've found a voice in this new album, one that we feel like we want to go out and share with the world.
"It's so important that you're genuinely excited about it, because the only people who would truly lose out if we did something that wasn't exciting, is us. We're the ones who go out night after night and play the songs, so yeah, I'm glad we didn't make that mistake," says Lovett.
And he adds that when you're travelling the world with your best friends, there's always a shoulder to lean on.
"We were friends for a long time before we were band members and partners. So if there was ever a moment when the road got tiring or where promo became like, 'Are you really asking us again why we called ourselves Mumford & Sons?'
"We just end up laughing it off, because ultimately, we're just a bunch of mates. We're very lucky."
• Mumford & Sons' new album Wilder Mind is out now.
