Welcome aboard Guy and nice first pen. It looks quite similar to my first, though you might have gotten a better fit at the tip than I did. I, too thought that grain looked like red oak at first glance, but I've never seen anyplace that sells just basic oak blanks. My guess on that wood is Tiger Caspi (aka Marblewood), especially since you noted it was pretty hard, but I could be wrong.
It's funny to hear so many people recommend the Sierra/Gatsby pens for beginners. I've probably turned maybe 50 so far and finally, just this week, picked up some of them. I suppose if I'd joined this site sooner, I would have learned a few less things the hard way. The bullet/bolt action pens that Mal mentioned are quite easy to turn and are quite the conversation piece. As far as slimlines, you'll find you can do an awful lot with them. There's a wide world of possibilities waiting for you and you are already on your way!