Thanks for the quick answer.
The NAS may support iSCSI I’m not sure I can! I was going to have a go at creating some NFS shares and retrofit W10 to use NFS. I hear that NFS and windows can be a pain but right now I’ve got one (maybe two) boat anchors if I can’t get the client and server to talk. Plus I know next to nothing about iSCSI.
Will let you know what happens.