Block display with attachment returning no results

I have a Block Display, which has two attachment displays attached to it. The Block Display itself doesn't return any values, which is fine, but the attachments do.

The problem I'm having, is that the Block Display still classes the View as having no results, and the Block is hidden. Is there a way to make the Block count results from the attachment, so the Block isn't hidden?

The workaround I'm using at the moment is to add something into the No Results Behaviour, so the block is always displayed... but that means the block is displayed when there really are no results to show. Which is far from ideal.

Maybe I am doing something wrong... or maybe this is a bug?

Thanks
RIch