Over here in the UK if we don't know a actors agents address we can send things via Equity which is the Actors Union and they will pass them on. I've used Equity a few times over the years and its been quite successful.
So any help, tips etc will be gratefully received

Oh and yes I have requested an address for the Actor I would like to send to in the forum with no replies. Since that was over a year ago I can only conclude no one has it lol
Cheers