The Location in the reference should be the gallery or venue of the exhibition.
To reference an individual piece of art use the Artwork on location guidelines.
You will need:
Creator’s name, Initials. (Year produced) Title of the exhibition. [Type e.g. Watercolours]. Place, Location. [Viewed day month year].
Dickens, L. (2021) The way I see it. [Watercolours]. Crciket Fine Art, Hungerford. [Viewed 24 February 2021].
In-text citation: (Dickens, 2021)