Dormer window leak into bedroom on floor below?

[Pebbles574]

Help. I'm at my wits end trying to work out what's going on here.

Town house with ground, first and second floors.
Top floor has dormer windows in the roof front and back.

Every time there is a particularly heavy period of rain, especially from a particular direction, we get water stains on the ceiling of the bedroom directly below the dormer.

I've had roofing firms out twice and spent nearly £900 on work - higher lead flashing, sealant all around window frames, tiles all checked, sealed under ridge tiles etc etc.

We've stain-sealed and repainted the ceiling twice, but it keeps happening.

Since they are dormers, there is no 'roofspace' to go into, so we'd have to take down the bedroom ceiling to look properly

Anyone had anything similar and worked out where it's coming from?

We had a similar issue and in the end a roofer stripped all the tiles off from the area on top of and all around the dormer. He then replaced the underfelt with new, relaid the tiles, concreted the edges and replaced the lead. He couldn’t tell exactly where the ingress was occurring but it worked!