looks like a cross trade - I can't see how they can both be sells and not have hit the price. Or are Merills after even more having moved the bid up to 100p a few days ago?
My guess would be a fund to fund trade at the same price, the balance picked up by the mm's - hence being ably to fill that 26K buy this am without moving the price up.
I can't see there is any way the mm's would take nearly 2% of a company in an illiquid stock just 3 weeks prior to results unless they had a ready buyer - and pay 0.5p premium - unless they know the results will be excellent.