No need to feel foolish Andy, we all have been there and done that as they say
Not sure of the difference between the combined or enhanced, I would guess that the enhanced is for something to do with running SATA drives as PATA (or IDE) as I said earlier but I am not 100% certain. If it seems to be working ok then I would leave it alone
The newer type of ribbon cable for the IDE devices is the 80 wire type as opposed to the earlier 40 wire type. The extra wires are earths so I dont really know why they make such a dfference but they do especially, as I have noticed, on some DVD writers.
I usually put the blue end in the mobo connector just because there is usually a blue connector on one of the IDE ports, usually the primary one, and because theres usually more distance between that end of the cable and the other two connectors which makes it easier to connect the other end to either 2 hard drives or 2 CD/DVD writers.
Again its not essential but its common practice to use the primary IDE channel for the hard drive, especially if its the boot drive.