Hello Graham,
There are only a couple of small differences:
Styling is different, as the lid is more similar to the Beogram 1800 in appearence than the 5500, and the output lead is fitted with two RCA plugs instead of the standard 7-pin DIN plug. The Datalink modul is, as far as I know, still mounted.
Beocenter 9300, Beogam CD50, Beocord 5500, Beomaster 3400, Beomaster 4400, 2 Beogram 4000, Beomaster 8000, 2 beogram 8002, Beovox S-75, Beovox MS150.2, Beovox RL6000, Beovox S-35, Beomaster 6000, 2 Beocord 9000, Beocord 8004, Beocord 5000, Form 1, 2x Beolink 1000, Beo4, MX3500, LS4500. Born 1993.