Sliding door double mortise lock

A quick learner from Fairfax, CA says:
Hello,
My sliding door double mortise lock is broken. The bottom mortise is stuck in the locked position. While the top works fine. I've removed the handle but cannot see any visible screws to remove the lock itself. The only piece with any marking is "made in New Zealand" the screws on the handle and lock are about 4 7/8 apart center to center. I'd like to replace the double mortise locking mechanism but don't see any way to remove it. Can you recommend a way to remove the locking mechanism and a replacement for it?
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Bob from SWISCO responded:

The handle set looks like a type with 4-15/16" hole spacing such as our 82-080. In that case, a mortise lock like our 82-268B or 82-238 might be what you need. Compare their dimensions to your old lock and see if one of these matches up. 

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