You are using what is called "domain masking". Your blog's address is actually http://subliminalmotion.wordpress.com but your domain name registrar uses a trick so that your browser thinks your address is actually subliminalmotion.co.nz at all times (even as you navigate through your website). This is not the same as "domain mapping", which actually replaces your address:
Bottom line: the title "Very high performance bicycles" comes from your domain name registrar. So you need to check your settings with your domain name registrar or contact them for assistance. There is nothing we can do for you on these forums because it's not part of the WordPress.com settings.