The rules for JSA (CB) say:
JSA(CB) may be claimed for only 26 weeks in any benefit year. When entitlement to JSA(CB) is exhausted, JSA(IB) may then become payable if eligible (see below).
If there is no entitlement to JSA(IB), a person can re-qualify for JSA(CB) in a subsequent benefit year based on contributions paid in the relevant contribution years, providing that there has been a break in of at least twelve weeks. S/he must wait until the beginning of a new benefit year before s/he can claim again.