Ok, the perfect way,is to steam them.
For years, I found boiling to perfection, without them waterlogging and breaking up, or remaing hard, was a bit of a black art, esp on an electriv hob.
Since I discovered peeling, then steaming, til soft inside, I get perfect patotoes every time.
Generally Maris Pipers, and a little butter, cream and black pepper. And then I use a potato masher to crush them, but then use an old fashioned fork to actually whip to a spun flume of carbohydrate goodness after a good crushing, to get the air in and make it light and fluffy.