Hi Clare, happy new year!
Clare is it possible to do a batch rdf import (we have several thousand Nomisma records we need to move over and one at a time will take too long :-))
No, Dédalo hasn't implemented a bulk import from RDF because, until now, current projects haven't required it. Instead, they demand the import specific information from OCRE, RPC, or other sources and publish their own data in Nomisma format.
Clare And/or is it possible to batch import via csv or another format?
Yes, Dédalo allows importing data in CSV format. You can refer to the documentation here and a video tutorial here for more information.
Note:Note: If this feature is commonly needed, it might be possible to implement it as a tool. The ontology map from Nomisma and Dédalo is complete, and the process works for one, so I believe it could be feasible. However, you may need a faster solution at this time. A script could be quicker than implementing it in a tool, but if the community requires this feature, it could be added to the TODO list. Any help here is greatly appreciated. :-)
You can see the Nomisma map in ontology behind the numisdata1262:

Tell me if you need some help.
Best