Unfortunately, when I switched on the ignition there was a warning "Ping!" and an amber warning light on the dashboard. Consulting the handbook told me that the warning light indicated a problem with the power assisted steering.
So, a quick change of plan. Walk to the Co-op to get the necessities, which takes me right past the garage. I left the key with the garage proprietor and did my shopping. They collected the car some time this morning. I don't need it urgently because we're not really going anywhere at the moment and if a problem had to develop, now was as good a time as any.
As to the mowing, it rained! Not much, but the drizzle was heavy enough that I thought mowing grass with an electric mower was Not A Good Idea. It's supposed to be dry tomorrow, so the grass cutting has been postponed until then.
Update: The car is now back. It seems that it wasn't a fault on the steering but a fault on the warning system which the garage has now cleared.