I am really surprised just how many web sites operated by UK businesses fail to comply with the UK Companies Act 2006 and the 2002 eCommerce legislation.
Most of the requirements of these laws (as far as web sites go) is just plain common sense in terms of reassuring web site visitors about the trustworthiness of the organisation behind a particular site.
They require, for instance, that a site provides the geographic address of the business operating it. Regardless of the legislation, this does serve to boost confidence in a web site as far as its visitors are concerned. Incidentally, current legal opinion is that PO boxes do not cut the mustard as far as the law is concerned. The geographic address should literally identify the business premises.
Limited companies are under much greater stricture and must disclose their registered address, country of registration and registration number.
At the end of the day, web site operators should take professional advice on these matters and should be wary if these issues are not raised by their web designers.