John Harrison (fl London 1743-1787), A bentside spinet 1759, London

the case of mahogany with wide holly and ebony stringing, shaped brass strap hinges, the faciaboard and name baton veneered with walnut, with holly and ebony stringing and mahogany crossbanding, the jackrail and soundboard surround veneered en suite, the five octave keyboard, GG to g^{3, with ivory naturals and ebony accidentals, on trestle stand with cabriole legs carved at the knees baluster turning above, wtih claw and ball feet inscribed on a boxwood plaque on the name baton Johannes Harrison Londini fecit 1759, the shafts of the top and bottom keys incribed J. Burr 1758}

The signature of the workman J. Burr also occurs on the top and bottom key shafts of a spinet by Joseph Mahoon which has been ascribed the date of 1742.  See Donald Boalch Makers of the Harpsichord and Clavichord, 1440-1840, third edition, editor Charles Mould, p. 499.