Dennis' brother-in-law Ken Ford was a member of the tank division when he served in Vietnam.
When he heard Dennis was gathering material for his album he requested 'Green Green Grass of Home'.
"I asked him 'why do you want that song?' He told me 'when we left Vietnam and all the noise of the guns and helicopters and landed at Whenuapei, it was just dead silence. We knew we had landed on home turf'.
"Even now, that is his favourite song," said Dennis.
When playing the album and hearing Dennis' voice, Ken became emotional.
"It brought back too many memories for him, arriving back from Vietnam with mates who had only one leg or arm left, or had their eye socket blown away."
Dennis said Ken didn't really speak about the war.
"When he came home, he went bush for three or four years and just stayed out there. He didn't want to be part of society at the time, but he is doing okay now."
Cambridge country music duo Michael and Ashley Cooper (Cooper's Run) also contributed a song to Dennis' album.
"We've known Dennis for quite a long time," said Ashley.
"Michael refers to him as Uncle Den."
The pair composed, Man From Vietnam.
"We are very proud of the song," said Ashley. "It's for all those people who fight in wars and we also wanted to do it for Dennis who we admire so much and to be thought of by him, to contribute, was overwhelming."
Marsh says he hopes the songs he has chosen will spark memories of elders and those who went before.
"In the past my Dad used to bless us when we'd leave home, so I thought Charles Tindley's hymn Stand By Me would be a fitting way to begin the album. It becomes a sort of blessing to those who are leaving to fight.
"We couldn't be there so the spirits of the ones that had gone before them like great-grandparents or grandparents would protect them."
Now based in Tuakau, Marsh has fond memories of performing at Frankton Market.
"I believe when I stopped playing there, that's when they let the traffic through." A portion of the proceeds from Lest We Forget will be donated to New Zealand's Returned Services Association.