Thanks to everyone who has replied so far. The ceiling height of the
existing bedrooms is around 2.5m, so it would be possible to lower
these by 30cm or so. As regards changing the roof from a hip to a
gable - would that require planning permission as well as the building
regs? If the purlins were removed where would the steels have to be
placed ..... this all sounds like it is going to be v.costly and
slightly beyond the scope of a diy project !!!