Ended up using the squash with a healthy roast dinner:
That's pork roasted in cider (with crackling om nom nom), beetroot likewise roasted in cider round the pork, cauliflower & leek in cheese sauce, mixed variety steamed carrots, potatoes roasted in goose fat... and mashed butternut squash. So, you know, the squash wasn't really central to the meal, but it WAS yummy, and very easy to prepare once the ballache of peeling it was over. I steamed it till tender and then mashed it with a bit of butter. That's it.
My cheese sauce recipe, btw, is a thing of beauty and a joy forever. Ingredients in the order of adding to the pan:
One small onion, finely chopped and gently fried in butter till clear.
A pint of milk.
A garlic cube.
A teaspoonful of wholegrain mustard.
Some cornflour to thicken.
And once it's thickened, lots of cheeeeeeeeeeeese.