Hi Debra
Could't find the surname CLARK, but did find the surname CLARKE in the index seven times;
1. Rev. W.R
2. patten, clog & basket maker
3. Coachman
4. Joseph, ready made clothes shop
5. Harnessmaker
6. Hotel, formerly Sweet's.
7. Coachman for 20 years and keeper of "Old Angel" Inn.
In your posting you did mention harnessmaking, so I will give you that reference (No.5), though it doesn't indicate a great deal;
".........and Sweet, who I think was an ironmonger. Clarke, the harness maker lived next door; you had to mount four or five stone steps (some of them projecting on the footway) before you entered his shop. Gillard, a shoemaker, Upham, a hatter..........."
Yes, not a great deal there. I can give the extract for the others if you wish? Maybe the coachman are related to harnessmakers?
I see your ancestor was born in 1846, whereas the book relates to residents of the 1820's and 1830's (or thereabouts). Though could still be related?
Les