It may be worth you getting in touch with After Adoption for some advice as they help with people touched by adoption including how to search. As your mum was probably born in Accrington they should be able to help as they deal with people who were born in the North of England. Their number is 0800 0 568 578, address Head Office,12-14, Chapel Street, Manchester M3 7NH and website address is
www.afteradoption.org.uk. There is a forum attached to the website so you will probably get plenty of advice there as well.
Pip
