Yep , I would reiterate
@jiberjaber 's comments above. Whilst you'd be more than welcome to refill your bidons chez Diggs I wouldn't take the Billericay route from Chelmsford for reasons outlined. The only reason to come via Billericay* is if you cut down earlier and come across through Ingatestone way (again, lots of nice quiet lanes).
*There are, obviously, other reasons to come to Billericay but for the purposes of this discussion etc.etc....