Patio lock lever broken

Your handle set looks like an older version of our 82-080. Now, we sell the 82-240 thumb lever by itself, but this is strictly meant to work on the modern 82-080. I'm not sure how well it will fit on your older model.

Considering it sheared off, you likely also have a major issue with the mortise lock. Consider our 82-268B as a possible replacement. You will need to remove the original to verify that it's the same design and size.

All orders can be placed on our site at your convenience. 

The length of the handle and the length of the 82-268B don't interact, so the size of one isn't relevant to the other. I would suggest removing and measuring the mortise itself to be safe. That will tell you for sure.