After a six-hour hearing, the judge Mr Justice Lloyd concluded it will take up to a month to be decided with a court case rescheduled for early December.
"I shall take some time to consider your respective submissions. I shall be out of London for three weeks, so I will not be in a position to make a judgment until December," he said.
Rajar is trying to have the case, in which TWG accuses the group of having flawed testing methods, thrown out.
Sally de la Bedoyere, managing director of Rajar, said: "We are pleased we have been able to explain our application for a strike out. We have always considered the case to be based on a ludicrous and innnacurate assumption and therefore we are confident that the TWG case will be struck out."
MacKenzie, chairman and chief executive of TWG, has long maintained that Rajar's diary system of measuring radio audiences is inaccurate and accounts for a loss of TalkSPORT revenues of approximately £1.5m a month.
In March this year, TWG issued a statement announcing that it was suing Rajar for £66m in lost revenue. TWG first threatened to sue Rajar in September 2003.
"Unlike Rajar we can't wait for our day in court -- and we want it sooner rather than later. We believe we have an unassailable argument and we are happy to leave it to a judge to decide on its merits," TWG said at the time.
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