Walter Briscoe wrote

The Royal Mail postcode finder might also possibly be of help:
http://postcode.royalmail.com

I use a site with similar functionality without the unfriendliness. I

fear to advertise it as my usage is probably not what is intended.

http://www.ukphonebook.com has telephone white pages and address/post
code lookup (offshoot of 118 080, limited number of free full lookups
per day)

and http://www.deformedweb.co.uk/trigs/coordinates.html
converts to/from OS grid references Postcodes, Lat long, telephone
dialling codes etc.
so you can always get a postcode to use with a travel planner website
or SatNav unit.

--
Mike D