Text taken from the 1935 Barnard Castle official guide `A Modern Town with Great Historical Associations` published by the Barnard Castle and District Publicity Society. Price threepence. (A little slice of history)
The building in the Horse Market with a somewhat elaborate front is the Witham Testimonial, erected to the memory of Mr. H. T. M. Witham who lived at Lartington Hall. Here the Mechanics' Institution has its quarters; including a reading room and a lending library.
Here also is the Barnard Castle Dispensary founded in 1835 and still performing a useful service to the sick poor of the town. On the second floor is a lecture room, and at the rear is a spacious music hall used for concerts and public gatherings. Here the Barnard Castle Choral Society, founded in 1856, gives its annual concerts. On Market Days (Wednesday) the Hall is used as the Market Hall for the sale of Farm Produce.
The buliding has recently re-opened (2014) after a long refurbishment and is now a light and airy community space and public area.
(Very little of this remains true today, the library was still open in the 1970s (I used to use it myself), the dispensary is of course long gone the town having modernised it's medical facilities a long time ago. The hall is still there and as bouncy as ever but it is not used for many public events nowadays, mostly used for bring and buy sales and elections. The farm produce is sold on the Saturday Farmers Market.