I'm a big fan, is the addres up-to-date?

Iron Maiden
Iron Maiden Holdings Ltd.
22-23 Old Burlington Street
London, W1S 2JJ
UK

Are these adresses up-to-date?
And if they are, what adress should i use?

Siegfried and Roy
c/o Siegfried and Roy Productions
1639 North Valley Drive
Las Vegas, NV 89108
USA

Siegfried and Roy
c/o Kirvin Doak Communications
7935 W. Sahara Avenue
Suite 201
Las Vegas, NV 89117
USA

Is this adress for John Nettles (known from Midsomer Murders, Bergerac) still up-to-date?

John Nettles
c/o Saraband Associates
265 Liverpool Road
Islington
London N1 1LX
UK

Hi everyone!
I'm a big fan of AC/DC and i wanna write some words to them and hope for a signed photo...
is the adress still up-to-date?

I'm a big fan of David Copperfield, i've wrote a letter to him, but i don't know if the adress is up-to-date.
Is the adress for him updated?

Hi!
I wrote a letter to Alice Cooper and requested an autograph, i used both of the adresses to make sure i could get a signed photo. But i got an RTS both of my letters
Is the adresses to Alice Cooper really up-to-date?

P.S fanmail rules! [rockon]