Hi
Have you any idea of dates here? Your other post shows a family in 1901. Are these the deaths you hope to find or an earlier lot? You can search the register index for BMDs after 1837 free on either
www.ancestry.co.uk or FreeBMD.rootsweb.com It is not full coverage but gives a very good idea of what areas and times people died. Ancestry also has the 1881 census free, as does
www.familysearch.org The latter has the International Genealogical Index on it which has many baptisms and marriages on it which might help you too.
Chris in 1066, who is the Sussex board moderator may well be able to help you with St Mary's burials as he is an expert on Hastings and that area and has numerous transcripts.
Andrea