No step in execution of a certificate shall be taken until the period of thirty days has elapsed since the date of the service of the notice under section 6, or, when a petition has been presented under section 8, until such petition has been heard and determined:
Provided that, if the Collector is satisfied that the defaulter is likely to conceal, remove or dispose of the whole or any part of such of his movable property as would be liable to attachment for the recovery of an arrear of land revenue and that the realization of the amount of the certificate would in consequence be delayed or obstructed, he may at any time direct, for reasons to be recorded in writing, an attachment of the whole or any part of such property.