Frankly, seeing as everyone went happily along with Hunt's assertion when he was Health Minister that Britain is now a 24/7 economy, so NHS workers can expect to work any of those hours, all weekend, way into the wee hours... (remember the photos HCPs took of empty tube trains at 7am on a Sunday morning, jeering at the reality that actually only HCPs and NMW workers are likely to work those hours?) ...
Well, given that no one cared about the sanctity of Sunday for those workers, I'd say a lawn mower at 8.30am is perfectly acceptable. I mean, that might be the only time some workers have to do household upkeep tasks.
It reminds me of my now late mother's horror of Sunday opening in shops, way back, and occasionally raised on MN today; her complete lack of understanding that for some people, late night or Sunday shopping might be their only option.
If we want the convenience of other people working unsocial hours, like supermarket delivery drivers and couriers, to ease our lifestyles, we have to accept that they might need to do household tasks at times that aren't convenient for the 9-5 massif.
The bouncy castle is a red herring, here.