Citizenship Ceremony Booking

After having automatically received a letter from the County Council inviting me for the citizenship ceremony, do I have to call them and confirm that I would be attending? The letter specifies the date of the ceremony so do I sit back and wait, or do I have to get in touch with them and confirm attendence?
I ask, since I am abroad at the moment. Thank you.

Nothing wrong in calling them & checking should you feel so.. that would be best place to get you confirmed answer!!

I understand, however, I ask since I am abroad and in a very remote location in the himalayas! with barely one network signal bar, the call quality is very poor and I am just about able to get online after waiting for ages.
Hence, I ask people from experience whether they called the County Council to confirm the ceremony or no action is required. Many thanks.