As mentioned in the third post it is already rooted. Also I believe I have it rooted correctly as when I set it up initially I could move a load of apps and saved a heap of space.
Interesting to note that you can't install once the memory goes below 20 MB and I can keep this in mind. That might explain what was happening as when I did the 6 MB install with 23 MB free to start with it seemed to gradually increase till half way on the install and them immediately complete giving a message insufficient Storage. Strange that it would give this when there is still 10% but if that's the way it is I suppose there's nothing we can do.
Thanks for your inputs.