Hi Mick,
Well, if, as I think you are intimating that James Adams 1781 is the son of William & Susannah Adams, it could possibly be William Adams & Susannah Sturdy are the parents, the last child I found for the marriage was Ann 1777 so they could have moved to Bardfield Saling after that date, their son James born 1774 Gt Waltham was buried in 1776 so they could have had another James, unfortunately I haven't searched for the burial of William senior so I don't know if he died in Gt Waltham or elsewhere. I'm afraid I'm a bit slack concerning burials, I usually only search them when I need a burial to prove something or I stumble across them by chance etc. I get over to the UK (and the ERO) on average every second year, between visits I accumulate a list as long as your arm of leads for possible ancestors so I'm not left with too much time to spare for burials.
I will get in touch with Kath (Essexbird) to see if she will check her records for Adams burials in Gt Waltham, to see if that could throw some light on whether William Adams & Susannah Sturdy could have moved from Gt Waltham. I suppose we must keep in mind that perhaps there was a different William & Susannah Adams lurking in Bardfield Saling!