“Ultimately, on an application such as this, the question is not whether the assurance provided by an ATE policy is better security than cash or its equivalent, but whether there is reason to believe that the claimant will be unable to pay the defendant’s costs despite the existence of the ATE policy. It must now be recognised, in my judgment, that depending upon the terms of the policy in question, an ATE policy may suffice so that the court is not satisfied that there is reason to believe that the claimant will be unable to pay the defendant’s costs. ”