Hey, thanks for the reply, I understand what should happen, and have indeed had this working in the past in previous versions. I probably wasn't clear with my issue.
So I'm using a character rig which already has multiple skins which I can choose between to see the sprites change (created several months ago in a slightly earlier version of spine). Revisiting this rig, I try to add a new skin. In the hierarchy window in the setup view the attachments directly under each skin placeholder disappear when I select the new skin. Selecting a previous working skin shows the attachments again in the hierarchy window. I assume that I shouldn't have to add attachments to each skin placeholder each time I add a new skin? I'm pretty sure I didn't have to do this when I set the file up? If I remember rightly, I only had to adjust the source location for each placeholder in each skin.