I notice there's a collection of Janet Frame editions for sale, some of them signed, at an upcoming rare book auction in Auckland. It's always worth checking the provenance of any celebrity signature, but as some of the items in the catalogue are attributed to the collection of Peggy and Bill Tramposch, who were friends of Janet's, these offerings look pretty reliable!
a snippet from the catalogue
The auction is at noon on Wednesday the 19th of August, in Auckland, New Zealand.
For further information see the Art & Object website and download their pdf catalogue: