Hello Stephen,
I found the baptism record on the internet, for William BAX at the General Baptist Church in Horsham in 1795.
On the same IGI Batch there are some of William's siblings:
Mary bap. 1802, Martha in 1799, Thomas in 1808, and Sarah in 1806.......all children of William and Martha.
There is also Hannah Bax, daughter of John and Susanna who was baptised at the same church in 1793, and
Joseph Bax bap. in 1784.....son of Joseph and Sarah Bax.
I then found the marriage of a Mary Bax to James DUNTON on Dec. 02, 1826 at Southwick, West Sussex.......which I believe would be the Southwick which is just east of Brighton and west of Shoreham-by-Sea.
This couple appears on the 1851 census at Brighton, and it says that Mary was born in Itchingfield...........I think it possible
that Mrs. Dunton is your William's sister since the 1851 census also says she was born "about 1803" making her a match for the one baptised in Horsham in 1802.
Slougham is only about 6 miles from Horsham, and it occurs to me that perhaps William was actually born at Slougham, but
baptised in the Horsham General Baptist Church.
I tried to find some of the other siblings on the 1851 census without success so far.
There is no record on the IGI at the LDS Family Search site, for another William Bax born in Sussex in 1795.
On April 30, 1821 a Sarah Bax married John AYLWARD at Itchingfield.
Oct. 3, 1810 Hanna Bax married Henry EDWARDS at Warnham, West Sussex (just outside Horsham).
I found Hanna and Henry living in Horsham in 1851, and the record states that Hannah was born in Horsham.
William's sister Sarah was baptised in 1806. I found Mrs. Sarah AYLWARD on the 1851 census and it says she was born a "about 1807" at Itchingfield, the same as Mary mentioned above..............the age of this Sarah also makes her a match for William's sister.
On Feb. 11, 1824, Martha BAX married Alexander McISAAC at Itchingfield............no luck finding them on the 1851 census.
Thomas "BOX" is the only close match on the 1851 census and he was born at Ardingly (about 6 miles due west of Slaugham) about 1809,
and living in Brighton with a wife named Mary in 1851........I don't have a marriage for Thomas yet.
Again, this could be a match for William's brother Thomas who was baptised in 1808 at Horsham.
I found a Thomas BAX on the 1871 census, also born at Ardingly, "about 1808" this time, and living in Lambeth, London without his wife Mary.
Now for your query regarding BAX CASTLE which I found in another location.
Did you see that Susan BAX (age 81) was living in the area on the 1841 census ? She would be Susan JUPP who married John
Bax Nov. 27, 1787 at Itchingfield.
There is a Susannah Juppe on the IGI, christened 23 Aug. 1761 at Nuthurst which is about 4 miles (as the crow flies) southeast of Itchingfield.
On the 1841 Census image I see that Susan BAX is living in "Two Mile Ash Green".
There are two other households in Two Mile Ash Green, one at "Post Land" and then, on the same census page
is a household at Lawsons Farm, a household at Dog Barking House, and next to that is Little Stammerham Farm.
Little Stammerham Farm can be found on the internet, with a map as to it's exact location. It is just under 1/2 mile
from BAX CASTLE, on the same side of the road.
Therefore, it is quite possible that Susan Bax was living in what is now known as the Bax Castle in 1841.
I hope you find this information helpful. Your query was interesting to me, since one of the new owners of
Bax Castle is a cousin.
Cheers,
Foxglove (Carol)