Thanks all for the comments.
Paul, the honest answer is I can't remember. Almost certainly the frame would have come from a plugin. I can't find it and I have a feeling it was part of a set that On One used to publish called "Perfect Effects". It was never updated for use with Windows 10 and so I can no longer use it. The frame would have been applied to the B/W version and the sepia effect then added to the framed image. If the sepia is added first, you end up with a sepia image and a B/W frame. I tend to create my own sepia effects using the colour Balance Tool but there are many plugins that provide a range of options.
I think you are right Brian. You can sometimes stare at an image and know something isn't quite right without putting your finger on it. As it was, It was a bit busy as an image but I couldn't do anything about that but I have reprocessed it to brighten the BG rather darken it. A darker BG looked out of kilter with the FG. Took a lot of masking (rigging) but just for you: