@BOAC:
I don't think we have any reason to suspect that any of the attitude indicators were not functioning properly - including the *** big ones in front of the pilots - unless someone is hiding something.
Unless the BEA is simply being coservative and admitting that it's unknown.
That said, were you and I in Vegas, I suspect we'd both bet the same on the likelihood of the PFD, RH, being functional. Were it not, I suspect at least something on CVR would have come up, but we do have the PNF switching to 3 ... perhaps a sign of non verbal communication regarding PFD being suspect?
Unknown.