Thank you both,
My initial research brought me to the conclusion that it was a piedfort, purely because of the condition but my husband says it definately isn't silver. Do they make cupri-nickel piedforts?
The annoying thing is we have had this coin some time, the emergence of the mule 20p made us re-address the coin but as they are both 20p when you do an internet search everything refers to the mule!!
Will hastily add photos for you to see because i don't think that it is a forgery, if it is, it is of excellent quality.
thanks again
Rachel