Red,
Not so sure it is as simple as it seems. I think that was a buy order from a good client, put to the MMs when spread was 26.5-27.25p, they raised the bid immediately and the trade went through minutes later. I may be totally wrong, but one thing we do know is the MMs are short of stock and if someone had sold 150k, I would have thought that would have been a good time to drop the price to shake out some more sellers, not to start raising it.
IMHO and I don't pretend to know how MMs minds work.
Trout.