I did it for Palace away and they had not arrived in time for the game so rang the TO and they said the tickets were sent to my adresse as the person logged in rather than the adresse I put in.
They did the dupes anyway and I was expecting the tickets to go to my adresse but they turned up 10 days after the Palace game at the adresse I put in.
Sods law I suppose but tickets should always be sent to the adresse of the person logged in to the site rather than the fancard adresse unless a different adresse is specified.
50 characters including spaces is a joke aswell, try it first and you may have to abbreviate words like Road "Rd", Flat "F", Kenny Dalglish "K Dalglish" or no spaces in the post code for it to accept the new adresse !
good luck - ynwa