<Tr> <Th> Postcodes (total) </Th> <Td> 23,317 </Td> </Tr> <Tr> <Td_colspan="2"> Statistics as at February 2012 </Td> </Tr> <P> The CH postcode area, also known as the Chester postcode area, is a group of postcode districts covering parts of north - west England and north - east Wales . Having previously roughly covered the former Chester district and present - day Flintshire county, postcodes for the Wirral Peninsula (CH41 - 49, 60 - 66) were transferred to it in 1999 from the L postcode area . It includes Birkenhead, Chester, Ellesmere Port, Neston, Prenton and Wallasey in England and Bagillt, Buckley, Connah's Quay, Flint, Holywell and Mold in Wales . </P> <P> The approximate coverage of the postcode districts: </P>

When did wirral postcode change from l to ch