Mr Redman has sung all his life, but didn't really take it up until he auditioned at the Blackheath Conservatoire of Music and the Arts in England, at the age of 60. As a kid in Plymouth during World War II, with his father away in the navy, he received basic musical mentoring from his mother.
"My mother only saw him about three times in six years, so it was just me and my mother at home, and she sang and whistled all the time," he said.
Having already lived in New Zealand more than 10 years, and being considerably older than most auditioning, he was accepted for "general voice" classes in which he did three terms before finding his niche doing the jazz vocal workshop.
After returning to New Zealand it was a year before he could find anyone to record with. "I almost gave it away," he said.
Life for the couple changed when something went wrong with Jean's surgery in 2010 and a replacement hip was wrongly fitted. Despite intense pain, and ACC's acknowledgement of the misadventure corrective surgery was not performed in New Zealand.
It led to the decision to head back to England for five months for the surgery at Blackheath Hospital - "three minutes from the Conservatoire" - and remortgaging the house to pay for travel, accommodation and the medical expenses, possibly more than $50,000 in total.
It could take 30 years to pay off, but he said: "I don't care. It's got to be done, if it's to put a stop to the pain she's been going through."
As for the gig: "I've got over my embarrassment. I'm quite humbled," he said.
"It's a great thought - but if they'd asked me I'd have said no."