Did you reboot ?
What’s the output from:
lsmod | grep floppy
and the contents of:
gedit /etc/fstab
I did indeed reboot. Then:
keith@desktop-1:~$ lsmod | grep floppy
floppy 60184 0
gedit /etc/fstab
/etc/fstab: static file system information.
Use ‘blkid’ to print the universally unique identifier for a
device; this may be used with UUID= as a more robust way to name devices
that works even if disks are added and removed. See fstab(5).
proc /proc proc nodev,noexec,nosuid 0 0
/ was on /dev/sda1 during installation
UUID=737a2c42-905e-4796-953f-6e4a391cb057 / ext4 errors=remount-ro 0 1
swap was on /dev/sda5 during installation
UUID=ab03173f-8eca-4d28-b844-146e46934189 none swap sw 0 0
/dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
Lets see what happens if you install fdutils
sudo apt-get install --reinstall fdutils
then reboot.
No: just the same.
I can’t write successfully and can only change disks by re-starting Nautilus.
“Floppy Drive/Detect Media” crashes Nautilus after the first disk.
[edit]
This is taking up your valuable time, Mark.
Do you want to stop for now as I can copy essential files to my hard disk?
What happens if you run:
sudo gedit /etc/fstab
then comment out the line:-
/dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
So it now reads
/dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
The SAVE the file and reboot.
Still nor right. But I am conscious of taking up all your time.
I suggest that I transfer all the files that I can then, if you are still willing to assist, I shall list all the characteristics of the drive’s behaviour and come back to try again?
Do you want to try one more thing ?
Certainly - I’m just feeling embarrassed about using all your time!
What happens if you run:
udisks --unmount /dev/fd0
to unmount any floppy disk that’s already in there.
Then insert the floppy again and run:
udisks --mount /dev/fd0
then before removing it, run:
udisks --unmount /dev/fd0
again ?
keith@desktop-1:~$ udisks --unmount /dev/fd0
keith@desktop-1:~$ udisks --mount /dev/fd0
Mounted /org/freedesktop/UDisks/devices/fd0 at /media/disk
keith@desktop-1:~$ udisks --unmount /dev/fd0
Reads a disk that I insert.
Inserting second floppy, there is no way of reading it except by “right-click Floppy Drive/Detect media” upon which Nautilus crashes.
[EDIT]
Ah! I’ve got the gist of it now. If I use this method for every disk change it works fine without crashing Nautilus
what happens if you unmount the floppy with:
sudo umount /media/disk
then remount the next one with
udisks --mount /dev/fd0
?
Both unmount commands crashe Nautilus
Hmm … do you wanna come back to this at a later date then ?
or shall I keep looking ?
Your call 
I’m a bit like you, I think: I hate being beaten.
To be practical about it, I can at least copy the files even if it means restarting Nautilus for each disk - and there are only a few.
If you have any sudden ideas then please do come back to me, but for now I suggest we leave it here.
As usual I am in your debt and very grateful for the time you have taken. And I have learnt a lot in the process.
Cheers, Mark!
No problem
I’ll keep looking … so check back tomorrow or sometime 
Will do!
BTW: I now have a “udisks-downgrade” folder in my home directory as a result of our trials.
Can I delete it?
Yes … run:
rm -r ~/udisks-downgrade
if that doesn’t work … run:
sudo rm -r ~/udisks-downgrade
You should also be OK to do a system update … which will bring udisks back up to date.