What a load of codswallop!
Orange are no different from many other ISPs, like O2, Be, AOL & TT, in blocking all other providers' port 25 SMTP. So why single them out?
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU BB => 2010: Orange 16 Meg LLU BB