Now The Mission – the only venue that once pre sold tickets before announcing who their artist was - have a real conundrum on their hands.
Whereas Christchurch's AMI Stadium, where Diamond was to play there, simply cancel the booking, close their doors and carry on with whatever else they had lined up for the year.
Problem for The Mission, it's an event. An event on the HB calendar of regular events booked annually around this time of year, designed to boost The Bay's economy.
It used to be an excuse for a BYO booze-up in the sun, no matter who was on stage, but the ban on chilly bins put the kibosh on that.
It's happened before when tickets to John Mellencamp didn't sell, so promoters cancelled his tour (claiming other commitments), then replaced him with Tom Jones. Or when John Denver was killed, replaced by Julio Iglesias.
A problem, too, is that most fans were expecting the Barry Manilow-styled Diamond, and won't be satisfied with some second rate replacement.
I've never understood why they don't book Kiwi acts: the likes of Crowded House or Split Enz (a reunion). Or Lorde or Sol3 Mio.
Right now, though, they need to look at what's going on around Australasia in March. And while not in the know with what doesn't interest me, I do take enough interest to know that with Womad here, and Byron Bay's Bluesfest in Oz, both on that month, there's an array of alternate acts they could consider.
Bluesfest acts are renowned for spinoff shows here.
Not my cup of tea, but someone once booked for The Mission, the year it was rained out, is Lionel Ritchie.
He's at Bluesfest along with a whole raft of acts Mission patrons might enjoy; even a combo – similar but not too similar to 2014's Irish and British Invasion mismatch: their Ronan Keating, one Corr, one Spice Girl and Leo Sayer misfire.
Also at Bluesfest, and who would be more than suitable (and right up my alley), is Robert Plant from Led Zeppelin. Although Plant's one of those artists who's moved on from his Zep days, and with his band The Sensational Space Shifters, is playing a great firebrand set of folk, trance and world music, keeping himself real and truly relevant; even reinventing some of Zep's lesser known works along the way – not what diehard Zep fans would be braying for at The Mission.
Someone on Facebook suggested Leonard Cohen (someone out of touch who needs The 13th Floor). And quite a few rap acts, too.
Not Mission fare, sadly. And that's when it can all start getting silly and a bit complicated, with folks suggesting who could never sell out a venue that size in The Bay, or someone so huge – so popular – the venue wouldn't cope.
For the mess it'll create – Diamond fans not enamoured with his replacement; a replacement not anyone's cup of tea; or worse, a new fan base turning ugly or to scammers to get tickets – they'd be better off cutting their losses and make this the third year that the show couldn't go on.
I don't envy them at all, but then HOY people would have a lot more room to breathe.
Graham Chaplow is a retiree, volunteer teachers' aide and award-winning writer. Views expressed here are the writer's opinion and not the newspaper's. Email: editor@hbtoday.co.nz