One grave I'd never noticed before in Bunhill is that of William Shrubsole (1760-1806). Not to be confused with the hymn writer fo the same name this one was a chorister at Canterbury Cathedral for seven years. He became organist at Bangor Cathedral around 1780, but his sympathies for the “dissenters” were not well received there, as evidenced by these records:
October 1783. Mr. William Shrubsole, the organist of the Church, having given great offence to the Dean and Chapter, by his close connexion with one Abbot, late of this place, as by his frequenting conventicles, that Mr. Dean be impowered to discharge the said William Shrubsole from his place of organist, if the said Abbot (who is supposed to have gone to reside in Dublin), shall at any time hereafter return in order to abide in the town of Bangor, or the neighbourhood thereof, or if the said William Shrubsole shall be found to frequent any conventicle or religious assembly, where anything is taught which is contrary to the Doctrine or Discipline of the Church of England.
December 1783. That William Shrubsole be employed to play on the organ of our Cathedral Church till Lady-day next and no longer; that in case it should not be convenient for him to continue in that employment till Lady-day next, he shall be at liberty to leave it before that time, and shall be paid the full allowance to Lady-day next notwithstanding. (Lightwood, pp. 167, 168)
After departing Bangor, Shrubsole became organist at Spafields Chapel, London, in 1784, and remained there until his death. As the gravestone notes he was the composer of Miles' Lane (which I associate with "All hail the power").