I realise this post is now 10yrs old & as your mother was then 92 I am assuming she has since died.  
The records at Elswick Lodge - if they exist - will be unlikely to provide info about your biological father given your birth cert does not name him & your mother also refused to name him. 
But times have changed & this type of situation is one where we would now advise you to take a DNA test?   Have you already done so?