OK... So I have got access to the iSAMS developer portal and their documentation and it appears as if their API will let me create a batch web service which can refresh its data at a set time frame and output its data to me as XML...
I guess then it should be possible to get those various XML files and have them processed by Moodle...
Certainly this would save having to query the database directly; however I still feel that the direct to DB approach is going to have to be easier; although I am probably just highlighting where my skills lack in that statement more than anything else!