In which censuses have you found the family and which certificates have you got? Have you any addresses to look up? Are you able to check the certificate for Caroline? I re-checked my index listings and there is also a Mary whose birth is registerred in Newington a year after Alferd Augustus. I haven't got a suitable death in the indexes for William or Augustus senior. They may have gone to the US too or if they were sailors died off-shore or in an accident where their bodies were not recoverred. Let me know i I can help. I'd like to know about the 'siblings' too, if you have time to key it in.