gboulton - i agree that a bipe could be a good second plane given that the bipe in questions has a generous amount of dihedral and a long fuse. the problem i see with bipes is threefold:

1. they don't fly themselves. unlike trainers, bipes don't fly themselves. the best second plane is a high wing without dihedral or a low wing with dihedral like the WM super sport.
2. orientation is more difficult as bipes can look the same right side up as it does upside down at a distance. i've sent myself into a panick multiples times trying to reorient myself after being distracted and looking away from my plane or having the sun in my eye. what saves you is not that you can SEE the plane but that you can judge, due to your inputs, which way it's oriented. i would think that a beginner would have more difficulty getting out of that situation. i've seen people fly their bipes right into the ground, looping crazily all the way. i suggest, if a beginner is flying a bipe, a spotter (instructor) should be present at all times.
3. they are short coupled and thus have bad ground handling. it would not be the best first taildragger.

furthermore, they tend to be far more difficult to fly in gusty wind and less forgiving of pilot error. i would suggest that the bipe be a second plane of a two plane hanger rather than a plane to replace the trainer. ground handling, landing and flying are all more difficult in wind but that is accentuated with a bipe. just my experience. and bipes are generally not made for beginners and thus a little more fragile.

last but not least... balancing a scale bipe is very very sensitive. Due to the short nose and two wing layout, it is not easy to balance the bipe (imho). as such, the maiden should be done by an experienced person that checks everything before hand.

BUT... i love bipes, too. they just have so much personality.