Great seeing the 'then' and 'now' shots on Howard's weblink above. The enlarged shot shows the AutoCarriers and Ferry Works script on the gates. For those that were not at the ACOC National last year, held at Thames Ditton, it was at these same buildings that the vintage AC's, and the earlier Sociable and Box, were displayed and the ACOC plaque was unveiled (see the earlier postings for links to photos).
It's an intersting car in the shot outside the factory. Certainly 1910-1914, with its shaped tail, prominent hubs and substantial axle it may be an Austin 15, though that rear shape was quite a popular design then. One thing's for sure, it's not an AC Fivet of the period.