I put the vegies in with about an 50 minutes to go. Less if I parboil the potatoes.
Then I do the same as Dach. The meat comes out to rest (about 50 minutes after the veg has gone in), the oven goes up high and I move the veg to the top shelf in front of the fan which makes them go nice and cripsy. By the time I make the gravy, then the meat is carved the vegies are golden and crispy.
Now I really feel like roast lamb and veg for dinner....but we're having risotto. Couldn't be further from a roast if I tried!