I highly recommend calling inernal HR teams directly if you are making a speculative application.

Sometimes your CV will be overlooked as they are extremely busy and more than likely, your CV will be sent into a portal and not directly into their inbox.

If you send it directly to them on the back of a phone call, not before, it will have a much greater impact.

Remember, you will be much more attractive to an employer if your CV is not saturating the market. It looks unprofessional and it will annoy recruiters (agents & in-house teams) if they recieve your CV from multiple locations.

Finding the appropriate person will be quite simple if you use LinkedIn.