OOPs never mind - no sooner had I posted about this I found the paragraph I was looking for! In case it is of use to anyone else, here it is:
2.8 Resumptions
Persons are generally allowed to resume the BTWEA once. In exceptional cases and with due explanation, an applicant may be allowed resume the BTWEA for a second time provided there is less than five years since the claim was withdrawn. (Participation in seasonal type activities should NOT be allowed - see below).
In this way, persons simply resume where they left off. Once entitlement to the allowance has been previously established it is not necessary to receive a qualifying payment for a specified period. However, it is necessary to be in receipt of a Social Welfare payment immediately prior to commencing employment. The rate of payment is based on first qualifying Social Welfare claim.