Possibly George Augustus West, b. 09-Aug-1733, dsp. 07-Feb-1776, the second son of Lt-Gen. Sir John West, 1st Earl of De La Warr and Charlotte MacCarthy. In 1764 he married Lady Mary Grey (ca. 1740-1783), daughter of Harry Grey, 4th Earl of Stamford. George August West is mentioned a few times in the letters of Horace Walpole.
Life with Boswell:
Boswell was at a meeting in the Beefsteak Club in London on November 27, 1762, which was also attended by Colonel West of the Guards among others.