Brown roll rims - why me?

Brown roll rim mushrooms are moderately poisonous and look disgusting. And for some reason, they grow in profusion on my side lawn. For someone who likes foraging for edible mushrooms, this is a great disappointment.

These guys obviously like my lawn. Perhaps it's because I've a large birch and beech tree growing nearby. The mushroom bible (Roger Phillips) says they grow to 12 cm. On my lawn they can grow to at least twice that size - this one was 29 cm across (the lens cap is 8 cm).

If I cut the grass at this time of the year I have to remove these mushrooms before I mow or - as I've discovered the hard way - they make a real mess.

I cleared them yesterday, the second time in four weeks, and filled two buckets...

... the mushrooms weighed 9.5 kg.

 Why couldn't they be ceps, or chanterelles?

Update 2025

It turns out that these are actually Paxillus obscurisporus, closely related but much larger and less common. They were identified first by Pat O'Reilly of First Nature, and latterly confirmed by Francisco Verenciano, one of the chief identifiers from the Warwickshire Fungi Group.