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Jason O'Halloran has given his Honda Racing team the ideal start to its home round by topping the opening free practice session ahead of Shane Byrne and Lee Jackson.
The Australian rider missed out on Cadwell Park last year due to injury and had been relishing the race weekend having moved to the cusp of securing a Showdown spot.
O'Halloran made a late blast to the top inside the final 10 minutes as he broke into the 1m 26s bracket, duly followed by Byrne but the Be Wiser Ducati rider trialled by just 0.007s.
The MCE British Superbike championship leader was denied any final opportunities to improve on his time after Jackson, running in third, saw his Buildbase BMW expire at Coppice which forced a technical red flag with 65 seconds remaining in the session.
Showdown contender Luke Mossey claimed fourth on the timesheet ahead of Richard Cooper with Leon Haslam sixth.
Despite setting the early pace having not competed around the Lincolnshire circuit since 2008, Haslam rather over-reacquainted himself with the famous Mountain section by taking a tumble over the top. The JG Speedfit Kawasaki rider tucked the front wheel on the crest of the hill which threw him over the handlebars but Haslam walked away unhurt.
Having fallen with 15 minutes remaining in FP1, Haslam's best effort could only keep him sixth narrowly ahead his team-mate and local rider Peter Hickman.
Tommy Bridewell, on the lone Bennetts Suzuki after Ryuichi Kiyonari split from the team after Brands Hatch, grabbed eight as Billy McConnell and James Ellison rounded out the top ten ahead of Tyco BMW pair Christian Iddon and Michael Laverty.