A lot of cards expire in March please check as it will be necessary for you to renew your EHIC card in order to receive free health treatment when abroad.
You have to phone the UK 0044 1912181999 Monday to Friday 8am to 5pm press option 1. Have your NI number to hand they may ask you for details.
They will send you a form to complete and return before issuing a new card. New cards will NOT be sent automatically.