Thanks to those who have posted their thoughts & experiences.
After talking to my Doc, and seeing what has been posted I can understand now alot of what I have been experiencing.
The 'wind down' migrain as indicated by PAXboy is a common one for me, usually after a long hands on flight (for those unfamiliar with Western Australia navigating here in remote areas is fairly intense for the inexperienced du to lack of Nav Aids

), or after a hard/stressful week again like PAXboy usually the first day of the weekend!!
I can also 'sense' when a migrain is coming on, as opposed to a 'normal' headache so I hope to be able to kill it then with the medication perscribed.
My Doc also suggested making a migrain diary to see if there is a trigger other than (i know this sounds really wierd) stress relief.
my primary concern is about the drug and how - if at all - it may effect me, but I guess I'll have to wait untill I need to use it in anger
Cheers
P.O.M