Running Exclusion File in Database

[oddjob6214]

I have a data tab, in which i need to flag if a postcode has been excluded, this will be in a column next to the postcode

I have a Tab with all the UK Postcode areas, in which I then have a column next to it where I type the post code if it is to be excluded.

Ideally I need a formula or VBA Script that will flag a Y if it is excluded or a N if it isn't excluded