Kylie is the one I always forget, even though she was a top class ballroom dancer, but that is because she only appeared for one week in one series.
Some of those listed (e.g. John Byrnes, Andrew Cuerden) have quite high profiles being involved in teaching and other activities and so are easy to remember.
Hanna, I always remember as being a superb dancer, great personality and (not least) Christopher Parker's partner!