The ash seat-rails of the twelve chairs suggests they might be Scottish-made, as that wood is more common in chairmaking in that country. Some support for this theory is provided by the pattern of key-pattern inlay appearing in The Edinburgh Book of Prices for Manufacturing Cabinet-Work, 1811, pl. V, reprinted in David Jones The Edinburgh Cabinet and Chair Makers' Books of Prices 1805-25.
Scottish manufacture is not implausible given the provenance from Lowther Castle, Westmorland, which was aggrandised by Robert Smirke in 1810.
An alternative manufacturer is obviously Gillow of Lancaster, who allowed their craftsmen to sign their work in the style of the 'Bradshaw' signature on one of these chairs. An Isaac Bradshaw worked for the firm between 1826 and 1840, too late to have made these chairs (G. Beard and J. Goodison, The Dictionary of English Furniture Makers, Leeds, 1986, p. 99).
The chairs are likely to have been commissioned by William Lowther, 1st Earl of Lonsdale (d. 1844) for Lowther Castle, Westmorland following his employment of the architect Robert Smirke (d. 1867) to aggrandise the Castle in 1810. Their Grecian-scrolled form was introduced by the connoisseur Thomas Hope around 1800 at his London mansion museum in Duchess Street, and illustrated in his Household Furniture and Interior Decoration, 1807 (pl. 26 no. 2). Related chairs, with similar klismos-tablet rails inlaid with 'Grecian' black ribbon fret, were supplied around 1805 for the Egyptian dining-room at Goodwood, Sussex (House and Garden, April 1998, p. 121). The Grecian fret also featured amongst 'string' inlay patterns issued in the 1811 edition of The Edinburgh Book of Prices for Manufacturing Cabinet-Work (pl. V) (D. Jones, The Edinburgh Cabinet and Chair-Makers’ Books of Prices 1805-1855, Cupar, 2000). Twelve of the chairs feature ash-framed rails, which would appear to indicate Edinburgh manufacture, so it is possible they were designed by William Trotter (d. 1833) of Princes Street, Edinburgh.