You can send by whoever you like, just insure it like in a special del, it will cost over more as they are in S.Ireland, I sent a maxline II 250gig back when newish so it cost £250 for drive then so I insured it for that and it cost £10+ but would have been hlaf that if N.Ireland.
Get on phone dont use web, talk to Maxtor staff, give them your name, e-mail addy and postal addy, you get a e-mail which is a sheet of paper you print out, cut it at the dotted line, stick 1 part inside box with HDD (warning they ask you to wrap in antistatic bag or ruin warrenty, I keep orignal incase of this) stick other part on outside of box, all info including your adress is on this, you dont need write anything on box.