Roof/gulley leak

[LimonesLimones]

1930's house, semi. Erratic water,/leak problem every 2 years. Happens when heavy rain along with specific wind direction. Square bays. Only happens to both bays of mine and neighbours in between the semi part of house, not outside/drive side. Last time heavy rain neighbours along the road also had same problem.

Had loads of water gushing in from fastest corner of bay in upstairs bedroom and water in far corner of downstairs front lounge water..all on the adjoining side of house.

Various thoughts bring provided over years by roofers etc. Not fixed. I understand that these type of houses might have a joint joist forming the bays, though bays not abutting. No obvious roof tile damage, holes etc.

Previously neighbour had to replace ceiling in his front bay due to water damage and cemented gulley, last time got wet patch on internal wall that he says is coming from my house somewhere ..I have no wet patch on adjoining wall...single brick no cavity 1930's.

Recent views/recommendations by differing roofers are,:

As no felt in this type of house ...use 5U ..though never had it and no problem?

Gulley

Drains not wide enough? Been ok since 1930's!

Flashing has been checked and added to on chimney breast on neighbours house.

Appreciate water will find lowest point so might not be where it shows. Neighbour thinks shared problem i.e water enters somewhere then runs to either house possible along internal bay?

He suggests cutting back tiles and replacing plastic gulley?

Views please gratefully received!

Have paid roofers a few times but as such a rare event don't know not fixed until years later.

Thank you.

[wes56]

Posting photos of the bay roofs, and the chute/drain in particular, along with a general view would help quite a bit.