Last time I met the lead singer of The Remission Flow, he said "gigs" was a dirty word. He even dared to describe the Irish 7-piece as "the worst band to have on a record label", while sitting next to his label boss.

That was two years ago. So what's changed? As Darren Mulligan and I sat down in a South London café, the singer explained our previous interview (which had quickly turned into a discussion between his band mate and label boss about whether Christian bands should promote themselves) had helped clarify his views. Darren hasn't lost an ounce of his genuine humility, but as we're speaking in the same week of the band's first music video release its clear he's much more comfortable with promoting the band's work through traditional methods.

"Two years ago we didn't even want our picture taken but I've seen the benefit of it. God doesn't want us to be shy, retiring and hiding away. I'm more comfortable knowing why I'm doing it and I don't care whether someone is judging me for it. Bring the kingdom in - I want to do that. In order to do that I need to do some silly stuff like walk down a road in a hoody," he says, referencing the video for Before The Dawn.

The band's newly released second album Rhythms of Grace has attracted a flurry of reviews from across the world. The title is based on Jesus words in Matthew 28:30, "Are you tired? Worn out? Burned out on religion? Come to me. Get away with me and you'll recover your life. I'll show you how to take a real rest. Walk with me and work with me—watch how I do it. Learn the unforced rhythms of grace." (MSG)

Darren believes the record is "more expansive" and "more honest" than debut The Light That Floods. "It's not that the other one was insincere but I had these magic Christian goggles on. I was a relatively new Christian and life is great, life is amazing. Christ never promised me any of that. He never promised it would be all great but he said he'd never leave me and I could do all things. For me doing all things is getting by firstly, and secondly growing in character."

After quitting his day job last August the songwriter has had more time to hone lyrics that speak primarily of grace and truth.

"I became a Christian six years ago. For the first couple of years I was still trying impress God a wee bit, being good. Ever since the last record came out a lot of the fear left me. I started to understand this whole concept of grace. That he loves me regardless of what we do and he's sufficient. I can't make him more God by being a better version of Darren.

"The whole album came from that first song Grace and Truth. Instead of being all truth truth truth, hitting them with the gospel and even telling someone that Jesus loves them means nothing unless you're able to put your arm around them and say 'how are you'? Show the grace before the truth but both are essential. Get that balance right.

"I know I'm rabbiting, but I'm excited!" Darren says before taking another slurp of the coffee he doesn't like, but needs to stay awake (the singer only has two days to speak to English media before flying home and he's on a tight schedule).

Ultimately, Darren finds the band's growing popularity amusing. "Why would they want to listen to us when they've got Bethel and Delirious? and stuff?" he jokes. In truth he says the "honest answer" to my question "why the growing interest in The Remission Flow?" is "God is doing something".

Many have already commented on how Mulligan's lyrics are, although worshipful, very different to other artists. The singer puts this down to his habit of listening to very little music. He also refuses to write lyrics he can't relate to.

"I find it very difficult to relate to high lofty spiritual sounding things. Martin Smith had a song on Premier Radio this morning about soldiers or something, I'm laying my life down for Christ or something. And maybe he is but I can't relate to that. When I think of my life I know how much I'm falling short so I couldn't sing that with any integrity."

The final track on the album is It Is Well and is based on the famous hymn. But why do the band sing, "It is well with my weary soul"?

"You're the first man to notice that! My wife brought it up one day and said it was a bit of a downer. I suppose as a human I get tired. I get melancholic. This is dark but I don't think humanity and being alive is all that great at times. An awful lot of us are weary every day.

"My soul longs for that time when I don't have to wait anymore to be with him. I could not sing 'it is well with my soul' in a rejoicing manner. I couldn't do the happy clappy thing. I don't think there's anything wrong with admitting your weakness. I'm not the happiest guy on planet earth. I struggle sometimes."

Regarding future opportunities the band are most interested in partnering with churches on mission. Remission Flow aren't a typical band that promoters can book, partly because they've been known to stop playing after two songs, leave the stage and personally pray for and minister to teenagers in the audience. They're unashamed about breaking any perceived rules around what a gig (forgive the dirty word) should look like.

"We'd hope to partner with a church for three or four days and do smaller worship seminars...and talk about what it's like to live a life for Christ in an honest way. You can still make an income through that. But mainstream labels haven't cottoned onto that yet.  They're still putting 10 bands in a van and getting them to play four songs a night each and we can't do that. It's not authentic."

I put it to Darren that his band are Irish, they have a heart for ministry and they are up and coming in the Christian world...so how fed up are they with being compared to Rend Collective?

Laughing, the singer says: "You're a dangerous man. I'll be very careful what I'll say here. Seven times in the past few days I've heard people say 'these guys are the like The Rend Collective'. We are nothing like The Rend Collective in any way shape or form! Musically we're miles apart. Nothing in common! I think lyrically we're a wee bit closer but Rend are more mainstream. They went down that route that we felt uncomfortable with but they're seeing massive results. It's not a route we can go down.

"I've all the time and respect in the world for what they've done but I couldn't do it. I know we've done the video and stuff but you won't see me in a tweed jacket!"