[2] Irwin has experienced success on both short circuits and the roads, with runner-up spots in the 2022 British Superbike Championship, 21 points behind champion Bradley Ray,[1] and again in 2023 by a half-point to teammate Tommy Bridewell.

[12] Irwin returned with PBM in 2017 after signing a new two-year deal with the Cumbrian team,[13] where he would take his maiden win in British Superbike with victory in the first race of the Silverstone round,[14] ending the season in 12th place once more.

[17] 2018 would see a sharp upturn in form for Irwin in British Superbikes, as top 10 finishes in all but four of the races that year - including a win at the Brands Hatch finale[18] - saw him make the showdown for the first time and ultimately take 3rd place in the standings behind Jake Dixon and champion Leon Haslam.

[21] The switch failed to repeat the previous year's successes, with Irwin and JG Speedfit Kawasaki splitting by mutual consent in the aftermath of the Snetterton round, which he had missed with a virus.

[23] The year did bring some success, as he took another win at the North West 200 with a final lap overtake on Quattro Plant Wicked Coatings Kawasaki teammate James Hillier.

[29] Irwin would return in 2022 with Honda[30] where he would enjoy by far his most successful season to date in British Superbikes, taking second place in the standings[31] including an opening weekend hat-trick of victories at Silverstone[32] along with a double at the Brands Hatch finale.

[1] On 8 July 2023, Irwin finished in second place in the final British Superbike race at Snetterton, narrowly missing out on a win to his teammate Tommy Bridewell, who secured a hat-trick in the competition.