I'm currently learning the Nocturne No 5 by John Field - it is grade 5. Not hard to learn and very beautiful!
Maybe some pieces from Schumann's 'Kinderszenen' - I've learned the first one and the well known 'Träumerei'.
Some pieces out of Grieg's Lyric Pieces are around grade 5, too - the Arietta is beautiful, and so are a lot of others!
There's quite a lot of great music that is not that hard...
Ohh, I almost forgot - there are the etudes by Stephen Heller (I've found them thanks this forum). I'm learning some pieces out of op. 45 (1,2,15,18) - some of them might be around grade 5, too. Opus 46 has some easier ones...