Had a letter today saying 'we sent something to your client and it came back, tell us their new address'.
Never heard of the client, but rang and cleared security (/facepalm number 1) by using the information HMRC had sent me.
I explained the situation and that the individual was probably an employee of one of our clients and once I knew which one I could find out the new address for HMRC. But of course giving out an employer's name to someone is a breach of the Idiocy Act of 2010, as who knows what someone could do with that information.
So I told the nice lady there is no way I can help them unless they can tell me anything about the client. She said there is nothing she can say, so I said good luck on tracking them down and hung up.
I hope it wasn't anything important HMRC wanted to send.