I understand your frustration with Ancestry. The reason the searches throw up name and date variants is that their data of older hand-written BMD records is based on transcriptions by volunteers who are told to write down what they see, and not what they think should be there. This is why my great-grandfather, who had the French Christian name Georges, is in the Ancestry records as a boy called Georgia!
Also, although this is not the case with your particular research, people do not always know an exact name or date, so the search will include near matches as well as exact matches.
Having said that, I have also found that some family records are missing for no real reason, so I can understand that you are a bit fed up.
You might also find it handy to look at the online parish clerks project
http://www.onlineparishclerks.org.uk/ which contains links to parish records for quite a few English counties. This is an ongoing project, so if you don't find what you need now, it's worth checking back in about a year's time.