Calls related to tasks not showing up in Task Subpanels

So you added a one-to-one relationship between calls and tasks?  I think, if that's true, it should be a one-to-many relationship.

I have gone back and edited the relationships in Studio again - making it a one-to-many relationship as you suggest.

My instance of Sugar had deleted my previous relationships but was still displaying them in the list which is why I was getting so confused. It seems to be working now - thank you for your reply!