When showing that the cleaning firm is bogus, Sherlock shows a suspect a 404 error screen on his phone. But the top line of the phone screen shows the cleaning firm name, as if he was doing a search for the company name. A 404 error would only show If he entered a url for the company website.
Kitty repeatedly refers to Sherlock's pet tortoise as a turtle. This may be a deliberate attempt to annoy the pedantic Sherlock of course.