Hi Jenn,
They will let you know approx 7-10 days after your interview although I know of people who have had a phone call the next day.
They will tell you the course date when you get there, I think that they are running them all the time.
Everyone at my assessment got through to the 2-1 interview and the maths test is not multiple choice but is really not that difficult and as i said before the pass mark is only 50%.
Good luck and let us know how you get on