Hi, Please see attached pics. The existing door handle is from Citation Doors this number is printed on the inside 919213 Patent 1973 (see attached photo).
I think the replacement part is:
Surface Mount Sliding Door Handle Assembly, 4-15/16"
Product Code:
82-005But I'm not sure. If so, I'd like to order one. Alternatively, I think the internal part would probably be enough. I think that would be:
Sliding Patio Door Internal lever lock
Product Code:
82-225That appears to be out of stock however,
Please let me know what you think.
Kind regards,
Richard