search the marriage index on www.lancashirebmd.org.uk
and find this entry
Lancashire Marriage indexes for the years: 1850
Surname Forename(s) Surname Forename(s) Church / Register Office Registers At Reference
GREEN Charles LLOYD Mary Ann West Derby, Register Office or Registrar Attended Liverpool REG
if you click on the reference number that appears you get a partially completed application form to order a copy certificate, or you can find the marriage on Freebmd.rootsweb.com and order online from the GRO. When it says 'Registrar Attended' that means they didn't marry in the 'established church' (CofE) and often means an RC church. From the Hibernia site http://freepages.genealogy.rootsweb.ancestry.com/~hibernia/m...
you can see that they married at St Patricks RC Church in the Toxteth Park area.