Similar thing happened to me.
It was only due to a paragraph in a newsletter from my former flying school, advising PPL holders of the JAR variety should be taking a peek at the renewal date.
I did, and found mine had expires two weeks previously without my realising it. As KDCW says, five years is a long time, and with what we fork out to the CAA surely a reminder notice wouldn't go amiss?
However, on the positive side, they did also renew my RT licence so that the two dates are now synchronised.
