HI Sue,

Found the solution...just use direct sql in the query manager instead
i.e

RESTORE DATABASE [edw] FROM DISK = 'C:\RobinWork\Backups\dbBackup_Source\.EDW.bak' WITH REPLACE, STATS = 20

this will do restore to the actual NDF physical filenames within the bak file .However in SSMS it just wants to use the concat of the dbname with a numeric sequential suffix instead...must be a bug. See image below you can clearly see the ndf names it generates