Award notifications were required before you could add tax credits to a claim, where the claimant had received an interim payment.
The handbook also states you need to calculate the number of days between the date of notification and the end of the award.
However you should be able to (in theory) obtain the above information from the helpline.
I think it will depend on your local office policy on whether you require notifications or not, as by now some of the claimants will have lost/destroyed the original notifications.
