Justin Sherwood and Steven Liquorish took a win apiece as the Porsche GT3 Cup Challenge GB headed north to Croft for rounds seven and eight (21/22 July). Championship leader James Birch secured a double podium finish but failed to win a race at a round of the series for the first time this season. Nevertheless he was able to extend his lead to twenty points. There was also a first overall podium finish for Mark Cowne.QualifyingWarm and dry conditions greeted the drivers on Saturday morning as they went into qualifying. Championship leader James Birch (Birch Racing) emerged as the pacesetter, claiming pole position after lapping the North Yorkshire circuit in 1m25.614s. Im very happy with qualifying today. Obviously the main aim, as always is to get pole position and we did it again, he said. Steven Liquorish (Team Parker Racing) was second fastest but trailed Birchs best time by over a second. Simon Blanckley (sibsport performance) was third ahead of Justin Sherwood (Team Parker Racing) as three tenths of a second separated second from fourth. John Ferguson (Ask Racing) was fifth on his first visit to the circuit, with Mark Cowne (Parr Motorsport) rounding out the top six. The grid positions for the second race would be the same as for the first.Round sevenAs the lights went out pole sitter Birch made a decent getaway to lead the pack into the first corner, Clervaux. However, fellow front row starter, Liquorish made a poor start and dropped to fourth behind the fast starting Sherwood and John Ferguson. Sherwoods good start put him on the tail of Birch as the field headed down the back straight towards Tower for the first time. Sherwood got a better run than Birch and darted to the outside before out-braking Birch into Tower and sweeping into the lead of the race. He then set about building a gap to Birch and by the end of lap four he led by over two seconds. Birch tried hard to respond but could not make significant inroads into Sherwoods lead and the gap stabilised at around three seconds. As the race entered the latter stages though, Birchs tyres began to go off and this enabled Sherwood to cross the line five seconds clear. A fantastic result for me really, said Sherwood. I got a good start and seemed to get a good run out of the chicane and then I was in front before the braking zone and I was on the racing line, it was a good move. Birch took second, a result which enabled him to extend his championship lead. We just ran too low on the tyres at the start and I was a sitting duck during the first three laps, he lamented. Fantastic from Justin, he drove a great race, Birch added.   Behind the leading pair, Liquorish battled back past Ferguson in the early stages but could not lap at the same pace as Sherwood and Birch, so ran a lonely third for the majority of the race, crossing the line just under 15 seconds behind the race winner. Liquorish said:My tyres started to go off at the end and I think once youve got to that realisation moment of youre not going to pull second in, its a case of keeping the car on the track. Mark Cowne was fourth and grew in confidence as the race developed; consistently improving his lap times in what was his first visit to the circuit. Blanckley failed to finish after a collision with the tyres at Sunny, an incident which ruled him out of the second race as the car was not able to be repaired in time. The second retirement of the race was Ferguson who coasted into the pits five laps from the end with a driveshaft failure.  Round eightLiquorish won the second race of the weekend after coming out on top of a titanic battle with Birch. Birch led away from pole as Liquorish again made an average start but this time did enough to hold second position into the first corner. From that point Liquorish shadowed Birchs every move. He looked the quicker of the two but try as he might he could not find a way through despite getting alongside Birch on a couple of occasions. However as the race moved into the closing stages Liquorish got a good exit out of the hairpin and tried the cut back to get alongside Birch on the start/finish straight. As Birch moved across to block, there was slight contact and Birch spun. This gave Liquorish a comfortable last few laps as he cruised to the flag to take his second victory of the season. Im chuffed to bits with it, said Liquorish. The team made a big setup change and it worked, the car felt so much better on the brakes. Birch recovered from his spin to finish second and limited the damage to his championship lead by securing the fastest lap of the race. I had a good start. It was a difficult race for me as I was on old rubber. Steve was with me the whole way, it was a good battle. I was having to be quite defensive in places but it was good fun, really enjoyable its just a shame we had a bit of a coming together at the end but thats just racing I suppose, he said. Cowne finished third to record his first ever overall podium finish. This was amazing but I blew the radiator three laps from the end and I was all over the place, said Cowne. I really had to nurse the car through to achieve my podium finish.ResultsRound seven: 1 Justin Sherwood; 2 James Birch; 3 Stephen Liquorish. Fastest Lap: Sherwood 1m26.640s (88.29mph).Round eight: 1 Stephen Liquorish; 2 James Birch; 3 Mark Cowne. Fastest Lap: Birch 1m28.229s (86.70 mph)Provisional overall points after round eight: 1 Birch 149; 2 Liquorish 129; 3 Cowne 90; 4 Ferguson 69; 5 Sherwood 63; 6 Neil Houston 60; 7 Peter Smallwood 57; 8 Mark Flaherty 48; 9 Guy Riall 39; 10 Tom Hallissey 8.Next rounds: Donington Park, 18/19 August