Thanks Graham. That works absolutely perfectly. I changed strCaption to ActiveDocument.TT.Caption as the caption field in my document which is updated is called TT. With this very minor change everything works. Much of what I am trying to achieve with my documents I am managing to achieve with code on the internet and making the necessary changes. This piece I have struggled with for weeks and even when I look at the solution don't think I would have ever got there.

Thanks again, I really appreciate your help.
Steve