I get asked this question on many web design and development projects. Here's the answer!
You must include certain information about your company on your website; it's a legal requirement in the UK and it makes good business sense.
For Ltd companies, each company should list its company registration number, place of registration and registered office address on its website as a result of legislation (First Company Law Amendment Directive) that was implemented in 2006.
- Gov.UK: Running a Limited Company
This information doesn't have to be on every page but it must be easily found. For example, you might want to put it on the Contact page like I have. Some websites have this information in the footer section of each page.
You know it makes sense
As well as any legal requirements, it makes incredibly good business sense to make it as easy as possible for anyone to contact your company. So, regardless of how you are trading whether it is sole trader, limited company, partnership etc, you should include contact telephone numbers, email address and a contact form.
It's true that some people don't like contact forms but if you include all possible methods, the user can choose the method they like best.
You may be concerned that publishing an email address will attract junk email. That's a risk but it can be reduced by efficient anti-spam filters that work on your email server (ask your web/email host) and by encoding the email address without compromising its usability (ask your web developer).
In addition, I think it inspires a greater degree of trust from your website visitors and potential customers if you display your business address (if different to your registered company address) on your website. Unfortunately, a PO Box address is not as good (in my opinion) so it's your actual address that will be best.