How is it Farmer Groby, who is so mean to Tess, recognises her in chapter 33 well enough to know she isn't a 'maid' but does not recognise Alec d'Urberville in chapter 41. In chap 33 it says:
"Two men came out and passed by her among the rest. One of them had stared her up and down in surprise, and she fancied he was a Trantridge man, though that village lay so many miles off that Trantridge folk were rarities here."
Trantridge/Pentridge seems about twenty miles from Buckland Newton, the nearest place I can find to Flintcombe Ash/Nettlecomb Tout, where Groby has his farm. The meeting in chap 33 is (I think) in Marlott/Marnhull which about eight miles from Flintcome Ash and twelve from Trantridge/Pentridge in another direction.