1914 Britain Penny - Norton Die Clash?

Not a die clash, but rather a phenomenon known as "ghosting".

This occurs due to the high relief and large surface area of George's bust on the obverse taking up so much of the metal in the coin that it actually causes the relatively shallow-relief reverse side to cave inwards, leaving a "ghost" impression of the bust on the reverse side. It's extremely common to see on George V pennies from 1911 to 1922 before the bust was modified to a lower relief, and is not worth additional premium.

And the Norton die clash (although I'm not aware of it being called that) might refer to the die clash you can see on the 1918 kings norton pennies, among other dates. There is a clash on the trident and also on the neck of George, and this is referred to as 'birds foot flaw' as it resembles a birds foot.

Here's some pics.

I think it's a die clash. Great photo .