I have to think that the Store listing is wrong. Take a look at
Thanks. This is now working well with a third party USB C to HDMI adaptor. The sound output initially was being directed to the Surface Go's internal speakers. Once I selected the TV output setting the sound went to the TV and muted the internal speakers on the "Go". The picture quality on a decent size TV and the sound level is quite good and now enables me to watch All 4 catch-up TV programmes for which Sony does not provide an app on my particular TV model.