Well I finally managed to get out there and test the new arrangement utilising an extension tube to eliminate the almost full extension of the focuser draw tube. I am happy to say, at this stage it looks as if it has sorted the issue.
I have attached a quick and dirty process, and I am now feeling a lot happier (I did not get a chance to redo my flats so there is a bit of vignetting going on). Hopefully will get a chance to do some further imaging later in the week.
The first image attached was the issue I was having, and the second is from tonights effort (3x15sec...3x30sec...3x120sec and 3x480sec).
Really appreciate the help from everyone.
Cheers,
Daniel