David,   I suggest that you write into Ofcom after they have made their
announcement and establish the position on adding modes.  My guess that they
will be relaxed.  From a spectrum management perspective I would not want to
see too much of the spectrum taken up by modes that occupy too much
bandwidth, especially if they are not spectrally efficient.   As Ofcom will
probably refer any request for changes of mode to me I suggest that in
making the request that one is fairly  general on type, e.g. data modes but
specific on occupied bandwidth, e.g. 200Hz or 500Hz, that way one won't get
pinned down too much and be able to experiment a bit, which is what Ofcom
want to encourage.

73 John, G3WKL