Hi and welcome to rootschat
Have you used
www.freebmd.org.uk to look for possible births? The 1881 census is free to search on
www.familysearch.org so that should be a first step too. You know where they died so have you got the death certificates to establish ages? They may be approximate, depending on who gave the details but every bit helps.
Their marriage will probably be on freeBMD too. Getting that certificate will give the names of both fathers. Lots you (and Mum) can do to get further back.
Do make sure you check everything for yourself though as other peoples' trees can be very inaccurate.
Regards
Andrea