condensation in pitched roof, poor ventilation, 

simple fixed by inserting short pieces of plastic water main pipe where the first layer of felt overlaps at the bottom, allowing air through the gap created and thro the pipe. if the pipes want to slip through the felt laps then simply fit a screw into the top of said pipe thus stoping it falling through

Pull that insulation away from felt air flow is blocked

Doesn't this indicate poor airtightness of the attic floor, letting in interior humidity into the cold roof space which then condenses? Just like it does on walls near windows inside the house?

Check the basement -if dirt floor needs vapor barrier. Venting will help but stopping moisture from entering is key to solving issue

Uninsulated loft hatch, to much heat escaping from the living quarters

They will be breathing indoors, cooking food or showering. Big cause of that

They will be drying washing indoors. Usually the biggest cause of that

Manthorpe lap vents mate

Tile vents will help if you put them near the ridge