In the event that you are claiming your tax credits remember to recommence them by July 31st. If you are unsuccessful to recommence by July 31st your payments may cease.
You should have received a renewal pack mailed to you in the mail. When you get it you would be able to renew online to make it more convenient. If you miss the renewal date, your payments will cease, you will be mailed a statement and will be required to pay back any monies that were not due to you. If you fail to do it by the renewal date by 30 days, you will be required to initiating a new claim.
After you have reestablished, HMRC will dispatch you an award notification inside 8 weeks of them getting your renewal. Your award notice will acquaint you with the amount you are qualified for.
In the event not claiming tax credits and unsure what you are qualified for, you can utilize the benefits calculator at Turn2Us.