The will of William Norman written 1794 states his cousin is Susannah Watts wife of John Watts
coachman to Lord Sefton.
The will of Lady Sefton 1819 mentions her coachman Richard Watts.
Is Richard the son of John and Susannah Watts who took over his fathers position after he retired?
Is Lancashire the place to start?
Biographical info on Earls of Sefton:
Charles Molyneux (1748-1795), 1st Earl of Sefton. He, presumably was the Lord Sefton referred to by William Norman in his 1794 will as being employer of John Watts . Married Isabella Stanhope (1748-1819), Countess of Sefton. It would have been her will in which Richard Watts was mentioned.
William Molyneux (1772-1838), 2nd Earl of Sefton. Acquired the nickname "Lord Dashalong" because of his habit of racing through London Streets in a carriage with 4 horses. He was a founder member of the "Four-in-Hand" also known as the Four Horse Club. Keen sportsman, seemingly anything involving horses. Member of Parliament. Friend of the Prince Regent. Residences: Family seat at Croxteth Hall, Liverpool, Stoke Farm, Berkshire and 21 Arlington St., London.
They may have taken some servants from Lancashire with them to London. On the other hand, they may have employed local staff. A coachman , obviously would have moved between all their residences. Charles, 1st Earl lost his father when he was 8. I don't know if he was brought up at Croxteth Hall or elsewhere. What I know about him is that he conformed to the Church of England as a youth and was rewarded with an earldom. It's possible that his guardians got rid of some old family retainers (Catholic ones) and replaced them with their own choice.
Molyneux Collection, see National Archives catalogue. Deposited in 4 places: Lancashire Archives, Croxteth Hall, Liverpool Record Office and Sheffield Archives. On past occasions I've looked at lists of items in the Molyneux papers in Lancashire Archives on-line catalogue LanCat. There's a lot of it. They'd held land there since The Conquest. Look at National Archives catalogue first. That gives an idea of what's in each local collection.
A pity 2nd Earl of Sefton died before 1841 census. I was going to suggest looking at his residences to see if there were any servants named Watts in any of them, perhaps son or grandson of Richard or John.
My 3xGGM had a brother-in-law, Tom Crossthwaite, who was a coachman. He lived in Winckley Square, Preston, where the "Quality" lived, among them the Cliftons of Lytham Hall, related to the Molyneux family several times over. I looked at "my" coachman's life and his family background. He'd been a servant and footman and groom. His father was an ostler (looked after horses at an inn.) Another older relative was a blacksmith. Some younger members of the Crossthwaite family were also coachmen.