If water is dripping behind your gutter it s probably because it was installed without any flashing over the back of the gutter.
Water leaking between gutter and fascia.
Assuming the gutters have the correct slope the main reason for overflows is that the gutters are full of debris and need to be cleaned.
When water drips between the fascia and the gutters the problem could be a compromised drip edge but it s also possible the gutters are overflowing.
When the roof shingles do not extend past the metal drip edge the water will suck back on the metal drip edge this is called capillary action and run behind your gutters.
Capillary action is a water activity in which water adheres to a surface and follow the surface.
The gutter apron will prevent the dripping.
I had a look and think the problem is due to flashing being receded.
Water leaking in behind the facia of your roof could be caused by a couple of things.
Gutters are supposed to direct water away from your roof and into the ground.
For example most ranch style homes have a 3 12 or 4 12 pitch roof.
Home centers sell a gutter apron in 10 ft.
Damage to the roof and fascia.
The fascia itself is upvc not wood thank god.
A gutter apron is a bent piece of flashing that tucks up under the shingles and over the gutter.
There doesn t seem to have water in the loft so there is no leak.
1 your roof sheets have a hole in them or your screws or nails or equivalent are not watertight anymore or 2 the more common reason is where roof sheets are cut too short or they don t overhang far enough into the gutter.
Unfortunately it doesn t always work that way.
Over time rain gutters often start to pull away from the roof allowing water to drip over the gutter sides or between the gutters and the walls.
It s a bungalow so quite easy to access.
If the gutter is clogged some of that water will back up on the roof soaking it.
On some homes water tends to drip behind the gutters down the fascia and soffit and then either down the side of the house or straight to the ground.
And it doesn t stop there.
As i only moved in recently i don t know how long fascia and flashing were installed.
Some of the water may leak behind the gutters down towards the soffit and the fascia.