[m654321]

Thanks goldfinger.  I have to say something very strange has just happened, following everything going so smoothly.
I removed the sda/sdb drives for the setup where LL was only bound to sdb's /mnt/DATA (ext4 formatted). It was working very well in UEFI as I mentioned in previous post.  I replaced this with the sda/sdb drives for the setup where sdb's /mnt/DATA was ntfs formatted. They were then changed around a second time and now neither setup boots to the grub screen. How is it possible that when I remove the drives and put them back, after using drives for another setup, that  the grub screen doesn't show on booting? Most peculiar ...

In order to supply you with the information you asked for in the last post I need to obviously reinstall grub and then hopefully boot into LL. I know how to do this with MBR (you showed me previously) , but is this different for GPT with the EFI setup?  The instructions for MBR that you gave me previously were as follows, where X is the partition number for LL's root partition:

sudo mount /dev sdaX /mnt 
sudo grub-install --boot-directory=/mnt/boot /dev/sda
sudo umount /dev/sdaX

then sudo-update-grub on reboot.

Shall I run this on my setup?

Regards
Mike

[gold_finger]

That is strange -- I don't know why booting gets messed up when you switch out the drives.

Re-installing grub is different with UEFI.  Unfortunately, I can't remember the steps for that; but you can use your live Ubuntu DVD/USB again and run Boot-Repair from that.  Just make sure you boot the Ubuntu disk in UEFI mode, then follow instructions for installing Boot-Repair to live environment and running the "Recommended Repair" on this page:  https://help.ubuntu.com/community/Boot-R..._in_Ubuntu.  That should do the same thing as you manually entering the commands (that I can't remember).

Boot-Repair will spit out a pastebin page with its results after you run it.  Save that page's address just in case it doesn't fix things.  It may have clues as to what's wrong.  Run Boot-Repair a second time if first time didn't work.

P.s.  If you get booting sorted back out, after you test bind access to NTFS partition, test out symlinking to the partition too.  Just navigate to /mnt/DATA and make a new folder called "Testing" on it.  Then just make a random test text file in it.  When done, create a symlink to your home with this command (substitute real username):

Code:

ln -s /mnt/DATA/Testing /home/username

Open home folder in Thunar file manager and see if you have access to that folder and can open the test file.

[m654321]

Many thanks goldfinger.
Success at last, but before I got there, here's a brief recount...

As my win8.1/LL2.4 dual-boot setup, with sdb's /mnt/DATA on an nfts partition, failed to boot after placing this setup back into the laptop (on two drives - sda & sdb), I then tried to boot into the live environment of Ubuntu 14.10 (DVD) in UEFI mode, to do the necessary boot repair that you suggested so I'd get my grub screen back. 

No luck: after initially downloading files from the Ubuntu live DVD, the process got stuck at the Ubuntu screen, and didn't boot, hanging indefinitely at the orange screen with Ubuntu + logo.  So, I deleted the LL partitions (again) on sda, and reinstalled LL to get the fully functional UEFI dual boot up & running again, with LL home directory installed as root.

When done, I then booted to Win8.1, gave sdb a drive label (i.e. D:), so that it was accessible in Windows, and did what you suggested and put a notepad file within one of the folders on D:, then tested for binding but LL failed to detect any notepad file in 'Testing': so again no binding.  I then did the symlink test you suggested, and it worked. 

Following the success with the symlink test,  I then deleted the contents of my bind-home.conf file, deleted all folders in Home (except Desktop), and symlinked all 12 folders in /mnt/DATA to Home.  It worked.  I'm now setting up win 7 in a virtual machine (VMs stored on sdb) and am curious to see if it all runs smoothly with the symlinking - so far so good...  Also interested to see if the VM will access the data folders on sdb.  I'll report back when this is done, before giving this thread a 'topic solved'.

Regards
Mike

[gold_finger]

Glad symlinks worked.  Obviously there must be something about a UEFI install that causes the bind method to fail.  Not sure why that is, but something to keep in mind myself whenever I finally take the plunge and get a new computer with UEFI.  (Current computers suit my needs just fine, so could be another year or two before I do that though.)

[m654321]

Just to confirm again that everything is working well with the win8.1/LL dual-boot setup with UEFI enabled.
The directories in /mnt/DATA on sdb are accessible by both OSes, without any glitches,  & also accessible by win7 set up in a virtual machine (Oracle Virtualbox) within LL.
A good job done - many thanks again goldfinger  for your help - without it, I wouldn't have been able to achieve this... ;)

I am now ticking this thread as 'topic solved' 

Regards
Mike

PS. I'll put together a tutorial on the UEFI enabled dual-boot set up a bit later, when I have a bit more free time.