Print and post a letter for Essex

I am an estates agent in the U.S. and am trying to find someon near Essex who could post a letter to a resident there who owns a property in Westcliff-On-Sea and also a home here in the U.S.

What I need is for someone to open a PDF file, print the letter, put it into an envelope and quickly send it Royal Mail first class service.

If this is something you can help me with would you kindly respond at your earliest opportunity?

Thanks in advance for your reply. I look forward to hearing from you!