How about Companies House?
Many IT contractors have their own companies, registered with Companies House. On the CH website, not only do they give the current directors addresses, but all former directors'. The filing history also details change of registered address.
I wanted my home address to be less traceable, so moved my registered address to that of my accountants. However, the previous address still appears, and there's no way of deleting that. Surely not GDPR compliant?