Sage 200 - Deleting Stock Codes

A colleague has copied an existing stock item to create a new one. This code has no transactions against it and needs deleting as it was created in error. However when I try and delete the stock item we get this error message.

We use Standard Costing and I believe this is the problem. But as the code was created and needs immediately deleting I don't understand why this can't be done.

Many thanks