Hi Rootschatters,
Thanks for all your help. Some information new to me, such as Alfred Haynes's mother's maiden name, is especially helpful, along with the birth registration in 1887. I'll clarify a few points that have arisen.
Alice married in Patching nine years later; at the time of Alfred's baptism her future husband, a Londoner, was 15 years old.
The identity of Alice FIELD. I'm sure this is the 17-year-old daughter of Henry Field for a number of reasons. She is the only Alice Field to be found in Patching around the time of the baptism. (Actually, in the 1881 census she and her parents are in Ferring but the address, North Down, is very close to Patching; in 1891 the family are in Patching.) There were two namesakes living in nearby Angmering at the time, but they would have been aged 13 and 7 years. I have spoken recently with Alice's nephew, her brother Thomas's son (the only one of his generation in that family who's still alive) and he's confirmed that there was some scandal involving his aunt although he doesn't know the details.
I don't think Alice's child can be identified with her brother Claude for the simple reason that Claude has his own baptism entry in the Patching register in 1886; it would require the Patching rector, Edmund Tew, being fooled into baptising the same child twice, and in any case, why the second baptism? If the family wanted to give Alfred to his grandparents and name him Claude the job would have been done and dusted after the first baptism.
BERRY is the maiden name of Alice's mother Elizabeth, and, as has been noted, a lodger, John BERRY, was living in Alice's household according to the 1891 census. And, also in that year's census for Patching, I have found a child, George Burgess BERRY, aged 4 years (which would have been Alfred's age) for whom I have a civil registration births index entry but can find no other record. I wonder ...
Thanks again, everyone.