Other mistake: At the end of the song "Wait," when Sweeney and Lovett hear Anthony running up the stairs, Sweeney runs behind the door to his shop. For a quarter second, as Sweeney places his back against the wall, there is a modern-day water bottle on the window ledge. This, however, cannot be seen on the DVD or Xbox, though on laptops and probably computers also, when streaming you can see it around 00:43:10. (00:43:10)
Answer: It's a common colloquialism in England, particularly with London and East Midland accents - people often pronounce 'th' as 'v'. It's poor english but very common, and certainly would have been common in the lower classes in London at that time.