My daughter sowed some banana seeds about 12 months ago. One seed
germinated and is now 6ft tall and visibly growing in our conservatory by
the day! The conservatory roof is 12ft max.
How high do they grow (gulp)

Do they survive outside? - We live in Leicestershire

If they have to stay indoors can they be "pruned " and if so will they grow
again (as was claimed at the NEC Gardeners World Exhibition)?