30.4.1806 call on Willoughby (Nic)
Shropshire Archives 3614/8/38 letters of administration of Mary late wife of Nicholas Willoughby of Queens Row, Pimlico 13.8.1825.  But it would be unusual for Godwin to have used brackets after the surname for the first name, it more often referred to something the person was known for, like an address or an author's work - perhaps in this case being short for Nicholson, Godwin's friend who was at that time in and out of debtors' prisons
Holdens 1811 directory:
Dobson Willoughby attorney 17 Cliffords Inn Fleet-st (? will PCC 14.2.1851)
Henry Willoughby esq Fig Tree-ct Temple MP for Newark 1805-1831 (will PCC 28.2.1850)
William Willoughby Assembly-house Highbury-grove (tavern keeper?)
William Willoughby esq Mitre-ct Fleet-st  SunFire 1803 to 1816 there (? will PCC 9.2.1830 gent Serjeants Inn Fleet-st)