What is a company’s name? The answer to that question (In English law) may be less obvious than it seems. Companies can change their name fairly easily, though they do have to register the change of name at Companies House. In fact, it is quite common for companies to change their names, and even for companies within the same group to swap names with each other.
The only thing that identifies an English company unequivocally is its registered number. People need to know which company they are dealing with. So English law requires companies to quote their registered number on all documents used externally.
A company’s registered number never changes. So what functions as a company’s name is its immutable registered number, not its mutable ‘name’ written in words.