Oh joy!  Something else on the house is falling apart!
I'm still pottering about in the loft and heard dripping coming from by the water tanks.  On investigation, the chimney breast is wet and there is water dripping from the felt and ridge board.

This shows the wet area on the chimney


And the water running along the timber


This is the roof from the outside.  You can see there is no lead flashing on the chimney, but the render has (im not entirely sure what you'd call it) a thicker bit round the bottom which sort of covers the edge of the tiles.


I'm hoping that the cause is just a crack in the render (there is one, but its raining too hard to get a photo from outside) and that the wind is blowing the rain into the crack.  Does that sound plausible?

My only concern is that the guy who did the new roof back in the 90s has done something wrong.  Is this felt meant to go all the way to the brickwork?


I'll get a photo of the outside as soon as the rain eases up.  Would appreciate your opinion as to the best way forward.  I've not really had much experience with roofs in the past

Cheers

Some old roofs, including thatched roofs, just used a mortar "fillet" around the chimney. This can crack causing leaks.

However you might find there is lead under the render - they may have rendered down over the step flashing so you wouldn't see any lead from the ground.

what do you think the best line of attack would be?  replace the cracked off lump in the corner and then stick some sealant into the gar between the render and the tiles?  or would i be better hacking the render off and replacing it all?

The first picture suggests the leak is high up near the ridge. I think it needs a closer look to figure out how it might be getting in. Could be that gap but impossible to tell from photos.

Perhaps pay someone to take a look and try sealer while they are up there but ask for a quote for a proper job.

You have step flashing by the looks of it but cannot see the cover flashing because of the render.

The ridge is always the weak point and you should have a saddle over the top of the tiles (under the ridge tile) it looks a bit dodgy in the area and repointing may help, have a good look up close and then another pic or 2.

There is some magic stuff on the market but it's bloody expensive, I'll let you know what it's called when my mate tells me.

Local roofer recommended by 3 people we know is coming to have a look tomorrow and see what he can find

Been talking to my next door neighbour.  He did a fair bit of the building work when the extension was built.  Apparently the ex-husband didn't want to pay for new lead, so there's a bit at the bottom and that's it.  The few bits that you can see in the picture is all thats there  

Well let’s hope it’s warmed up a bit by then because it’s a bit too cold at the moment especially for sealants and paint.

Glad you have managed to find someone to fix it, it’s hard to find anyone these days to do anything.