Assuming the 525 and 555 are direct ports (in England) of the 520 and 550 then the 555 should have the Sound, Picture, A & B buttons. Check the "Which Harmony to buy... lot's of pics" thread for more details.
H880, H659, Samsung HLN507W DLP, Yamaha RX-V2700, Tivo S3 HD, Sony PlayStation3, Oppo OPDV971H, Polk SurroundBar, SliMP3
