Have you ever let one get to maturity (and eaten it) mum?
I have - as you say they turn into huge lurkers very quickly if you take your eyes off them
They are fine, but not as well flavoured as some. The skin goes orange and fairly hard and they store moderately well. If the skins seem soft, use them up quick. I've cut dodgy ones up (skin and all), roasted them and frozen them for soups and curries before now.
I've never saved seeds as I have a Franchii packet which has loads in there, plus I grow other squashes nearby and they cross so easily.