Well, yes. And no.
Back in my stressed-out days I would hop in my Hyundai Excel (not an American car) and toddle off for a coffee and donut, to London from Toronto (Ontario) which Google says is 189Km, give or take. Depending on your definition of "Cornwall", it looks like about 350Km from Surrey into Cornwall.
So my coffee-run - there and back - would be roughly the same distance as the trip from Mitcham Junction to somewhere-in-Cornwall.
Now, regarding the distance I would drive to avoid eating a Taco, is another matter.
The Hyundai Excel was a comfortable little car, 4-speed, manual, and without exceeding the speed limit I could reach San Diego from Toronto in three days. More than once I drove around the 'States - Toronto to Seattle 3 days, San Diego + 2 days, Pensacola + 3days, Connecticut +2 days, supper, and drive home along the I-90 through Buffalo; total 10 days. I drove Toronto to Prince Rupert BC via the US in four days.
Cheers
Chris