There’s no actual law saying, “Thou shalt not mow before 10 AM on a Tuesday.” But common decency? Oh, that’s a law we all live by. The unofficial rule in the UK is to avoid mowing before 8 AM on weekdays and before 10 AM on weekends.
Why? Because your neighbour Steve doesn’t want his Saturday lie-in ruined by the sound of a two-stroke engine. Steve has dreams. Let him have them.
Also, don’t mow after 8 PM. That’s the witching hour for lawncare. The birds are roosting, the bats are out, and you’ll look like a madman with a headlamp.