After signing up for next month's Challenge Wanaka two weeks ago, the self-described ''hopeless'' swimmer is hurriedly preparing for what will be his first iron-distance triathlon and only the third event in his career with a swim leg - competing in the pro field no less.
But before diving in head first to his latest sporting challenge, the first priority for Allan (28) is marrying partner Amy Nunn (30) this Saturday at Wanaka's Rippon Vineyard.
Nunn shares her fiance's sporting passion, having completed the Lake Wanaka half race at Challenge Wanaka for the past three years.
Her involvement in the 2014 event will be as chief cheerleader for her new husband, who had originally planned a relaxed summer following his nuptials, including a break from February's Coast to Coast after six consecutive years of competing.
However, when a sponsorship opportunity came up for Challenge Wanaka - an event Allan has only competed in previously in a team - long-distance triathlon suddenly seemed an ''exciting and refreshing'' prospect.
''I've always had a desire to go out there and have a crack at it myself. It's all the trails I like to run anyway and roads I often ride, so I guess the curiosity was always going to get the better of me.''
Allan finished second in his first triathlon in October, the Highlands Triathlon Sprint in Cromwell.
''That was over in an hour so this one's going to be a bit longer.''
Quite a bit longer, in fact, although endurance sport is where Allan excels.
''Nine hours can be considered a shorter race for me in some of the events that I do.''
The real challenge would be the constant rhythm of iron-distance triathlon, he said.
''That's really probably what I'm least familiar with ... just constantly hammering the same muscle groups for a long amount of time. There's variable terrain in adventure racing; it's quite a different game really.''
Allan only started his training for the 3.8km swim last week and hopes to be out of the lake on the day in about 1hr 10min, ''probably about 25min behind the first pro and around 10min behind the second-to-last pro''.
Despite the predicted time deficit, he has one advantage in the water.
''I'm quite happy swimming in the lake and I've noticed that a lot of people find the step up to open water swimming quite daunting.''
He hoped to be among the fastest pros on the bike, but the run leg was his biggest unknown.
''In Ironman that's where it comes unstuck for people ... and I guess because I'm such an innately competitive person I'll be pushing the limits throughout the day, especially because I'll be behind coming out of the swim.''
Despite suggesting Challenge Wanaka had ''every chance of chewing me up and spitting me out'', racing in the age-group categories was not an option for Allan.
''The idea of entering in the pro field is to get an idea of what might be required if I was to do more of that sort of racing. I know if I'd raced age-groups I would still be curious what was required at the top level.''
For now though, training will take a temporary back seat, as Allan turns all his attention to marrying his ''best friend'' this weekend.
