There is no specific mention made with regard to the validity period of CC. Thus it can be concluded that the CC once issued is valid throughout the period of registration.
Re-Registration - De novo
Where a student has revalidated his/her registration by registering denovo, he/she will be given credit for the oral or postal tuition completed during the validity of his previous registration.
de novo registration which would place the candidate in the same position as if his/her registration has not been cancelled.
Thus for all purposes, the CC once issued can be assumed to be valid till the students registration period (either original or on re-registration). This implies that the CC is valid till the student gets through the examination.