Hi thanks for the replies. I'm running on an intel nuc with and external USB drive.
Setting the folder name manually to avoid anything windows unsafe does seem to work however not a very user friendly solution, the Mrs would would have no idea what that means so that isn't going to work.
So NTFS formatted drive - works ok for the filenames but a seems a recent driver update is causing massive corruption problems (I've experience this several times on power cuts, many posts on this but couldn't see an answer except to put the disk into a windows pc and run checkdisk, which of course then deletes anything windows doesn't like!)
exFat seems stable but doesn't support linux filenames at all, and tvheadend windows compatible filenames doesn't work with the folders as we have discovered.
Maybe I could try Ext4 next and lose windows compatibility altogether, is this an option for usb drives? how would I format the drive? And I really don't want to loose all my recordings yet again if that's at all possible.