Erroneous 10p

Hi,

There are a couple of similar posts on the forum (including one just below this one), but I don't know much about coins and would be grateful for any information about this one:



I received it in change a while ago and I think the year is 2014 - hard to tell because the final digits of the year haven't impressed properly. There is a small depression where the 14 should be, which is directly opposite a large blob of extra metal (slightly raised) on the reverse of the coin, below the lions.

From the replies to the other posts I assume that is unlikely to be a forgery but instead a defective coin. I'd be very interested to know whether there is a particular name for this kind of error, if it is common, and of course whether it is an interesting curiosity or valuable collectable :)

Thanks!