Yes, take some lessons if you can possibly afford it. I just passed yesterday--on the first try--and I would
never have done so without taking about 15 hours of lessons, despite driving for 22 years in the US. There are indeed a thousand tiny things that are different about driving here...unwritten rules about when/where you look, the exact method of using the mirrors, even some stuff about gear-changing. And
especially the use of the emergency brake.
They also do not allow hand-over-hand steering...and when backing up, you are not allowed to brace yourself on the back of the passenger seat and steer with one hand. You somehow have to crane your neck all the way around, steer with two hands and still manage to do the clutch and brake correctly. I spent the majority of my lesson time unlearning these habits--correct in New Jersey, at least when I got my license, but wrong in Britain.
On the test, I was asked to do a 3-point turn (they call it "turn in the road") and backing around a corner. I also had to do a hill start and a zillion roundabouts, but they did not ask me to parallel park or do the emergency stop. (I suspect I didn't have to do the emergency stop because of the skidding danger--the road was pretty wet.) The test took every nerve-racking second of 45 minutes, but at the end I got a pass with 6 minor mistakes. (You're allowed 15 so that was pretty good.)
I did one of those intensive driving courses--expensive, but I wanted to get the whole thing over with quickly. When my instructor met me at the train station, he said to me, "At the end of this course you're going to think I'm a right bastard, but if the test is passed, I don't care." I wouldn't go so far as to say he was a right bastard, but he definitely fit the criteria for "drill sargeant." Good-natured, but very tough on me. Of course, when I passed I immediately forgave him everything.