However, following the introduction of the Companies Act 2006 it is now a legal requirement to display your company’s registered office address on your website and any electronic communications. Most people will put this information on their contact page of a website or on the footer of the home page.
Didn't believe you on that requirement MadJock, but just googled it and sure enough:
Legal Requirements for a Registered Office Address | www.registered-office.co.uk