Team ABBA with Rollcentre Racing debutant Adam Christodoulou bagged the fastest time GT3 in FP1, whilst GT3 championship leader Phil Keen sealed top spot in FP2 for Barwell Motorsport.
In GT4, the #86 Toyota GT86 of Stefan Hodgetts and James Fletcher were quickest in FP1, with the #53 Nissan 370z GT4 of Martin Plowman and Richard Taffinder claiming the GT4 honours in FP2.
After bagging second in the final race of the Snetterton double-header last time out, the #6 Barwell Motorsport Lamborghini Huracan of Sam Tordoff and Liam Griffin sparked the session into life by powering into an early practice lead in GT3.
The Team Parker Racing duo of Seb Morris and Rick Parfitt soon battled to the top of the timesheets, before being toppled moments later by an emphatic lap time from the second Bentley pairing of Callum Macleod and Mark Farmer.
In the waning moments of FP1, Christodoulou – joining Richard Neary and Martin Short as a three man crew this weekend – shattered the Bentley dominance by sensationally storming atop the GT3 standings by eight tenths with an impressive 2:01:287 lap time.
In GT4, category debutants Hodgetts and Fletcher in the #86 GPRM Toyota GT86 clambered into top spot ahead of the #99 Stratton Motorsport first-time season entrants Stuart Hall and Gavan Kershaw in a Lotus Evora.
Both were soon split by the invitational entry of Adrian Barwick and 2007 GT3 title winner Bradley Ellis, with the #46 Optimum Motorsport Ginetta grabbing second, narrowly denied FP1 honours by 0.007 seconds.
FP2 began with the #24 MacMillan AMR Aston Martin Vantage of Jack Mitchell and James Littlejohn setting the early pace, topping the standings by six tenths ahead of Matt Griffin and Duncan Cameron in the Spirit of Race SA Ferrari 488.
Griffin halved the deficit to Mitchell at the front of GT3 after 10 minutes however, with Championship leaders Keen and Minshaw in the #33 Barwell Motorsport Lamborghini Huracan battling into fourth after a disappointing opening session.
In GT4, Jan Jonck sealed a provisional Macmillan AMR double pole, guiding the #42 Aston Martin GT4 to the quickest time before being beaten atop the standings by Plowman and Taffinder in the #53 Nissan 370z GT4.
In the waning moments of the session, Keen reasserted the Lamborghini’s strength, battling to the top of the FP2 with a lap time of 2:01:995, eight tenths ahead of the chasing field.
Despite missing Snetterton, Century Motorsport’s Ginetta G55 GT3 outfit made a successful return to the series in FP2, with new pairing of Charlie Robertson and Aleksander Schjerpen leaping up to an impressive third.