Double Knockhill winner Ben Barker maintains top form Ahmad Al Harthy heads Pro-Am1James Sutton third fastest on return to Carrera Cup GBBen Barker was the fastest man in the Porsche Carrera Cup GB at Rockingham yesterday during testing ahead of rounds 15 and 16 of the season. Barkers best lap in the early morning session set the mark for the day when rain arrived before the second session.After winning both races last time out at Knockhill, Barker (Parr Motorsport) was right on the pace at Rockingham in the opening test session, posting a best of 1m20.195s to head Jonas Gelzinis (Juta Racing) and James Sutton (Redline Racing). In Pro-Am1, Ahmad Al Harthy (Redline/Oman Air) narrowly headed the times while Will Goff (Goff Racing) set the Pro-Am2 mark.The opening session set the times for the day as light rain before and during the second session prevented any improvements. Although it was dry enough at times for drivers to run slicks, the leading times were nearly 10 seconds slower than in the morning. That keeps the momentum going from Knockhill, said Barker, who got his weekend off to a perfect start before also setting a representative time in the later session. Gelzinis was also quick in the damp and ended the day second fastest overall thanks to his best morning time, less than a fifth of a second down on Barker.Sutton made a strong return to the series ahead of his first races of 2012 and went fastest of all in the later session. The team thought it would be a good idea to go out in the rain, said Sutton. It was a chance to see what it was like and we learnt a bit: it was a fun session.Less than half a second covered the next five drivers as Andy Meyrick, Sam Tordoff and Daniel Lloyd from Team Parker Racing joined Michael Meadows (Redline Racing) and Rory Butcher (Celtic Speed) in a closely bunched group, all of them potential race winners. Like all of the drivers, Lloyd took the chance to run in the damp conditions. It just builds a bit of confidence if it is wet for the races on Sunday, said the Carrera Cup GB Scholarship winner.In Pro-Am1, only 16-hundredths of a second split the top two drivers as Al Harthy and Derek Pierce (JD Pierce with Team Parker) set the pace. Al Harthy was just relieved to have run in the opening session after being delayed on the way to the circuit. After travelling from his home in Oman, he was held up by a road accident within 15 miles of Rockingham and missed the first 10 minutes of testing.  Once in the car, he was quickly up to speed and edged Pierce with Victor Jimenez (Redline/Oman Air) and Keith Webster (Redline/Marque One) close behind.