Thanks for the reply Linux,
Just came in from the garage to see if anybody had an answer. That's what really put me off, was the fact it talks about in in the owners mannual and the repair book that I have. They make it sound like you can just reach in there and take it out, no worries at all! The only way that I could even SEE the thing was with a mirror. And the other thing that was confusing was that a 3/8 rachet was too big and a 1/4 was too small. It makes since now that you say it is a 5/16. What I did was exactly what you suggested. I flushed it through the heater hose with the bottom radiator hose removed (I was replacing all the hoses also).
Seems like great minds think alike, huh?
Thanks again for your thoughts and help.
BTW, I come to England a few times a year with my job, always have a blast. Usually come to the Cambridge area, they have some great pubs! Cheers.