Hi jean - May prove to be a little difficult if she did not wish to name the father ??
Last I can fnd for Mary is in the 1901 census and she is a housemaid at Bannockburn House and lord knows what would have happened in the following three years.
You could possibly try an enquiry on Rootschat and see if they can come up with anything, but it is a problem with illegitimate births, have the same problem countless times and unless she applied for paternity etc. Hopefully someone from Rootschat may be able to put you on the right path..they are more knowledgable than me LOL