Attic condensation

Hoping someone can help here. I have a dormer bungalow and I just found a lot of condensation in the attic. When I bought the house I got the attic insulation upgraded and floored (c. 8 yrs). I did notice condensation once before but TBH never really up there. It is seems more like condensation as it is all over one side of roof kinda like top middle and end rather than concentrated in one area. I can see that the side with condensation is black liner all the way down and other side seems to be half way and then has a white liner and seems to move more in the wind but that could be wind direction. Is it more likely to be blocked vent, too much stored blocking air flow (where is air supposed to come in?) or a leak? Apologies but I am a clueless with no idea of DIY (in case that wasn't obvious!! ) but would like to have some idea of how this works before I get a professional in so I am not paying for something that isn't needed. I tried googling but it doesnt make sense they all talk about vents which I don't see. Insulation is wool and is right out to sides. I can't see gable ends as too much stuff there for tonight to move. House about 24 yrs old. SemiD. I will try take everything out at weekend to look properly but just what should I be looking for? Apologies again for what probably seems like basic questions but I am in a bit of panic mode here. I put a dehumidifier up there for now to try help but I am away until late tomorrow so that won't be long filling up. Thanks for even reading this!