I have been wondering about the Battle of Britain 50p, which I find fascinating.
 
	A couple of points.
 
	There exists three distinct types and maybe 8 variants (metals etc).
 
	The Mint claims it was not an error and was deliberate. This can be seen in the technical announcements of the coin.
 
	BUT the Mint issued a secondary specfication of the coin with the denomination.
 
	 
 
	The questions:
 
	Is there any other Decimal Coin without a denomination?
 
	If so, is there any other 50p without a denomination?
 
	Have any other Decimal coins had a secondary (replacement?) specification presented by the MInt?
 
	Does the Mint have a requirement to place the denomination on coins?