Problem PARTIALLY solved by adding
/dev/LogicalVolume1/Volume1 /home/jollyj/server ntfs defaults,uid=1000,grid=1000 umask=007 0 1
to fstab by
sudo vim /etc/fstab
Check your own uid and gid by typing id in terminal, and personalise your volume and mnt point directories.
EDIT: OK umask is part of the problem. I can either have control over the mounted point, and nextcloud will complain, or nobody has read/write access and nextcloud will let me in but I can’t do anything with an empty /data/ folder. WTF. “Mark as Solution” has been removed.
EDIT 2: Now I’m getting http error 500 when accessing the IP, and HY000/2002 when accessing phmyadmin. Searching for a fix.