iOS 8.1.3 - iPhone 6 touch screen unresponsive

I updated my iPhone 6 to iOS 8.1.3 last night. Seemed to work fine last night and early this morning.

Now my touch screen is unresponsive. I can swipe up to reveal Control Center and swipe down to reveal Notifications - but can't interact with them.

I can't shut off my phone (can't swipe across after holding down the Sleep/Wake button). Is it worth doing a hard reset? Anybody else having this problem with an iPhone 6?