Foraging for fungi

I've been picking Shaggy Ink Caps from the front garden in the last week or two. It's very satisfying to be able to pick some of your breakfast from the lawn!

In the last week I spotted another type of fungus growing in the orchard grass. Well, it wasn't hard to spot, really, being about 10 inches in diameter. But I have no idea what this one is. Have you?