Hi again Lizdb,
The records I found came from FindMyPast and I've since checked the NBI. I found no suitable burial records for Rebecca on there and several Sussex burials for George but probably none of them were the correct age for your George.
I guess you've found the marriage record but if not here is what I found on SMI......
At Eastbourne 8th January 1773, George Boniface (Aldingbourne lic) married Rebecca Chapman (otp) and the witnesses were Lucy Chapman, R Brown and Thos Cobden.
There are some children, in Aldingbourne.....
Elizabeth Tregus Chapman (1773)
George Chapman (1775)
Rebecca Lucy (1777)
Then possible baptisms...
George Boniface, son of George and Elizabeth, was baptised at Eastergate 20th Jan 1745/46
Rebekah Chapman, daughter of Nich and Eliz Chapman, was baptised at Eastbourne, 8th Jan 1749
I checked the Appledore Parish records, which served one purpose, in that it confirms there are absolutely no births or marriages for anyone with the surname Boniface from 1700 onwards.
Hope this helps a little, although I realise you probably already have the information.
As for a photo of Appledore, well there is a very nice country pub next to the Church, so I can feel a lunch in the summer beckoning