American Gothic will never get a widescreen release anywhere in the world, because the show was never filmed in anything other than a 4:3 format.
The show was made back in 1994/95 for a 1995/96 transmission. At that time, widescreen TV was almost unheard of, and hence the show was filmed in 4:3 only.
Thus, the DVD set will be the exact same format that was shown on UK and US TV!
P.S. The woman who played Caleb's sister, actress Sarah Paulson, is seen in the "Serenity" movie as the ghost captain of the ship towards the end of that final part of that film!