Many thanks for your reply,
I have tried the first by typing into the terminal and got no change, the second attempt also did not change anything when trying to write a file, the 3rd came back with a list of files first for example....
-rwxrw-r-- 1 500 users 1.5G Aug 9 15:07 Man.of.Tai.Chi.2013.720p.Webrip.x264.AC3-FooKaS.mkv
drwxrwsr-x 9 500 users 0 Jan 4 2007 Movies
The other command just said permission denied, i also tried to sudo it still denide, one thing i noticed on these I have to type /home/pi/Desktop/U not just the /Desktop/U does this mean I may have played the mount somewhere wrong ?
I don't get how something that should be straight forward can be giving me such a problem, I really dont want to format the sd and start again but looks like I may be left to try this

I shall paste my line from fstab....
//192.168.1.3/admin /Desktop/U cifs rw,username=admin,password=mypassword,workgroup=WORKGROUP,file_mode=0777,dir_mode=0777,uid=pi,gid=pi,forceuid,forcegid 0 0
What should i check on the nas drive should I make any changes there maybe ? its odd how windows and mac both have no issue with this nas drive and folder.
Many Thanks again.
Gareth