Sorry if i sound cynical at all. I am assuming from your previous posts that you are a wannabe ATCO who wants to get started with a good employer possibly as an assistant.
You can obviously navigate round the internet so i dont quite understand why you need someone on here to give you the address. If you can't even find out an address like that then I think your chances of becoming an ATCO are pretty slim.
Suggest you try looking on their website, or it could possibly work if you try sending your letter to the Manager of Air Traffic Services, Newcastle International Airport, Woolsington, NE13 8BZ
Anyway for your information, Newcastle throw all speculative applications in the bin