Brett Rumford is one of five Australians at even par and six shots off the pace on a day when 55 players shot in red figures.
Nick Cullen, Richard Green, Marcus Fraser and Wade Ormsby are alongside Rumford and while sharing 56th are far from out of calculations with three rounds to go.
Ryan McCarthy and Jason Scirvener are both 1-over, Daniel Fox 3-over and Nathan Holman continues to struggle with his game at 4-over and near the tail of the field.
Shinkwin, who lost a dramatic playoff to Spain’s Rafa Cabrera Bello in his last start at the Scottish Open more than a month ago, showed no signs of rust in his return to the game reeling off eight birdies against two bogeys in his round.
The 24-year-old made the most of good early morning conditions to set the clubhouse target and with rain arriving as the afternoon groups teed off his score held up.
"I've had five weeks off but the confidence has still been there, even when playing at home,” he said after his round.
“I didn't do too much the first two weeks but then I got out there and I was still swinging it quite well which was quite nice.
"My iron play to be fair was probably my strongest part but everything was good, and if everything is good you can't really score bad.
"I'll just keep trying to do what I have been doing. I'll warm up the same, I'll try and sleep the same as well and hopefully the weather holds up."
England’s James Heath, South African Dylan Fritelli and Swede Pontus Widegren share second at 5-under with a group of eight players, including last week’s winner Julian Suri, a further stroke back.
Defending champion Paul Peterson is at 3-under while pre-tournament favourite, Thomas Pieters, struggled to a 1-under 71.