If you are operating as a limited company you now (as of 1 Jan 07) have to display your business name, registered number and registered address on your company websites as well as all printed and electronic communications.
Not sure this regulation is that well known, so thought it would be worth sharing here as I know there are some UK operators here.
for more info check out:
http://www.businesslink.gov.uk/bdotg...3788946&r.s=sl
or
from companies house
