I know what you mean Tilly2. Some veg doesnt seem to stay hot for very long after serving, especially cabbage and brocolli. I always serve on heated plates too and pour the gravy on top.
At Xmas when Ive lots of different veg, I put them into a large casserole dish with lid, when cooked and keep them hot in the oven until everyone is sat down with turkey on the plate. Then place the casserole dish on the table. It seems to stay piping hot until everyone has helped themselves