Map Chart

Hi, I'm trying to create a UK map chart by clicking Insert > Maps (from the ribbon in excel). I'm using Office 365. My data contains county e.g Yorkshire, Devon, but I don't seem to get a valid chart. Where can I find geographical data I should be working with? I'd like to be able to do charts at different levels of address; so county, postarea (e.g BD, FY, M) outward postcode (e.g BD14, M16) and full postcode level. I'm not sure what excel recognises.

Many thanks