I sent a letter and SAE with US stamp on to the stage manager on: 20th April 2015, and the beginning of May 2015, I recieved this note back asking for donation in exchange for a signed playbill, understandable i guess.
address I used was:
Stage Manager of ' Something Rotten',
St James Theatre,
246. West 44th Street,
New York
NY 10036
USA