Monthly turnover £11,000 x 12 months = £132,000 annual turnover.
1.4 million divided by £132,000 = 10 years before a profit is made on that work (ish; I know add-ons, price increases, new accounts, etc)
Stick 1.4 million in a bank and I wonder what the monthly interest payment would be?
I think the window cleaner would be selling for £140,000 and just has made an error with his zeros.