i'm looking to change the family name back to irish by deed poll.
My family surname is Hampson i have been told the irish translation is o'hAmhsaigh.
Can anyone confirm this is correct and could you translate the name 'Sean Mark Anthony Hampson'

Based on this:
http://www.ancestry.com/facts/Hampson-name-meaning.ashx

Seán Marcus Antaine Ó hAmhsaigh

But there are several alternatives for both Mark and Anthony.

You don't necessarily have to do a deed pole. For instance, my name is English on my birthcert, but Irish on my passport. When I went to get my latest passport, I had to provide proof that I'd been using my name in Irish for the last two years.

I can give you some "behind the scenes" insight on the process if you contact me privately:

tZoe --AT-- lavZabit --DOT-- coZm

Remove the Z's.

That only applies if you are an Irish Citizen!

After a lot of searching through numerous "bad" books on names and surnames, I finally found Edward Maclysaght's. He built on Patrick Woulfe's Irish Names and Surnames (1923)
Slán