This may not be the right home for this query … but here goes.
If I already “own” http://www.xyzblanketyblank.co.uk but find that “xyzblanketyblank” is not available at WP obviously I will have to register something else, lets say http://www.upplander.wordpress.com
If I then map my existing domain to http://www.upplander.wordpress.com, what will a user of my site see in their address bar?
I have found the answer to this situation if you register a bespoke domain with WP bit cannot find the answer if you already have a domain name.