No idea whether you could learn or not offhand :-) except that Marna claims to have bad balance (as does Pete), but both ride fine... You'd prob need to borrow Marna's bike though, or Bec's, as mine would be too big (plus these days I do not have beginner-suitable bike). I would be happy to assist, though, if you come round the park sometime!

I started uon off IIRC by lowering the saddle enough that he could more or less push it along with his feet - that way you get the idea of the balance before having to also think about pedalling.

I do not know what the 56a Centre is, so no :-)