Clips for sliding door lock

I see what you mean. The bad news is that this retainer clip isn't sold separately. There is a good chance that you'll need an all new handle set.

I'd be happy to help with that, if it's something you wanted to pursue. Before I suggest anything, though, I'd like to see the mortise itself so that I can have a better idea of how this door locks to the frame. I can then see if anything in our inventory functions the same way.