Wet patches on ceiling/wall - external wall/bungalow

[Swell1]

Hello, where our internal wall meets the ceiling (it's an outside wall on our bungalow) we have damp/wet patches right across. The gutters are clear and when I look in the loft I can see a hole in the roof liner above this area so I assume this is my issue but would one hole cause wet patches right along the wall? I plan to remove the tiles but thought I would ask if one hole could do this.
Thank you

 

[datarebal]

More likely poor insulation at the perimeter .
Check again in the loft .

A hole in the underlay isn't a big issue unless there is an actual roof problem

 

[Swell1]

Thanks, the outside is rendered up to the fascia boards. When looking from the loft, the view is limited due to the angle it slopes to so we can only see the roof lining and the roof beams.
Thanks again.

 

[Wayners]

Lack of insulation.
Cold spot and the warn air causes damp spots.
To fix.
Tack board along the roof trusses inside loft then pack insulation up against boards. This allows the cold air to rise up in the loft while the insulation is around the edge.

You don't want to block air getting in loft ramming insulation around the edges.

You can Google that

 

[Swell1]

Thank you, I think I understand what you are suggesting, is this done just over the room with the damp/wet patches? Also how far up should the boards go?
Thanks again