First off - no worries - people forget all the time - what are they gonna do - arrest them all?
I wouldn't do anything. Let someone ring or write you (they usually send a letter spouting off a bunch of stuff about it being against the law to not report, etc, etc.)
Then, whenever that happens, simply ring or write them back (you will be instructed by the letter or phone call) and say you forgot - they will then re-schedule you.
Easy peasey mate!
