Rob, in a recent similar thread of mine one user posted there similar thread
http://www.iceinspace.com.au/forum/s...light=phd+pete
Which may help you as its about your situation. Make note of his last post.
http://www.iceinspace.com.au/forum/s...4&postcount=19
I dont know why this did not occur to me before. As this user had very similar problems to you.
Regards
Fahim