Hmmm, I found this website:
http://web.me.com/dearmanmollett/Dea...y/Jenkins.html
The Turbeville bit keeps making me think of Tess of the D'Urbervilles, but looking at the Jenkin(s) bit, I found some other baptisms for children of Lazarus Jenkin at St Nicholas:
Thomas 12 Apr 1778
William 20 May 1781
Margaret and Jennett 17 May 1788
William being born in 1781 matches the William on the website, so it does look as if Lazarus Jenkin's children went by the surname of Jenkins, not Lazarus. So "Hopkin Lazarus" could well be your Hopkin Jenkins.
It might be worth you clicking on "Contact" and sending the website owner an email.