Kirckman (also spelled Kirkman) and Shudi/Broadwood were the predominant builders of the 18th century in England, with an almost industrial output.
In the 1780’s/90’s both firms started to make fortepianos  also, which were similar to their harpsichords: their fortepiano designs basically did not differ.
Very special in this particular Kirckman piano is its length: 2.58 m.! Inside, above the soundboard there is a wooden frame (taken out for the photo) covered with paper. Is it meant as a dustcover? – that however, does not explain why the treble is not covered. 

The miniature is of an unknown lady by Pierre Louis Bouvier, 1808.