I used baking paper to line the sides of the loaf pan. It makes it easier to remove the cake from the pan for serving.
The candied grapefruit can be made beforehand. I made mine the night before and let the slices cool overnight.
Keep an eye out when cooking the candied grapefruit. Be sure to stir once in a while to prevent the sugar syrup from boiling over.
Try to cut the grapefruit slices as thinly as you can.
You can use grapefruit juice for the icing as well.
If the icing solidifies, add more milk or juice and mix thoroughly until it is pourable.