http://www.ashurst.com/doc.aspx?id_Content=929

This seems rather relevant:

“Ginger groups.

There is, however, an
extra concern for bidders using a
scheme: in addition to achieving the
approval of 75 per cent of votes cast at
the meeting, they also need the
approval of a majority in number of
shareholders voting. As a result, a
relatively small group of disgruntled
shareholders can tilt the balance.”

So a lot of shareholders with tiny holdings voting against cd, it seems, be effective in rejecting the offer.