Thanks for these three replies, Vonne.
No, there is no occupation stated on the marriage record or any of the bapt. records (at Brighton, then Preston) of the seven children of "my" Nicholas and Susan. And see further below ...
Yes, I have the will (made in 1720) of John Beard (d.1722). That Nicholas (son of William) is also mentioned in several other wills (his grandfather's, his father's, and those of several uncles etc). But sadly not one of them makes any reference to his even being married, let alone naming his wife or any of his children. He is, as you say, also a witness at the weddings of three of his sisters, but with no hints about any wife! Water, water everywhere, but ........
And in a Conveyance of Quaker-related properties in 1735, one party is "Nicholas Beard of Brighthelmstone, shopkeeper". Since William Beard's property at his death in 1730 had included "shopps", it is highly likely that this Nicholas is the same man as in all the other records above.
WHEREAS there is no specific info. about the other Nicholas, following his baptism in 1686, son of Richard and Mary. And in the 1705 will of Richard Beard (d.1713), there is mention only of his brother and sisters, his wife Mary, and his only daughter and heiress Elizabeth (now Streatfield). And that info. about his daughter is repeated on his burial stone in Rottingdean Church. So what became of that other Nicholas is a mystery. He might have died (but no burial found). But he might have been disinherited. And he might have been the man who married Susan Barnham.
So there's my problem. I still can't say which Nicholas married Susan!
Mike