Slipped tiles, gap in felt (pics)

Inside the roof there is ripped felt which is caused by slipped tiles because I can see daylight from inside. The felt is tucked behind the wooden beam there but it's not attached to anything.

This is where the two slopes of the roof meet, see next pic


Should the felt on the two slopes be joined to each other?

I'm getting a roofer out but i wanted to know what it should look like normally, the last roofer that fixed slipped tiles didn't seem to do anything with the felt and the batten that I can see looks like it has a bit of mould on it so i'm wondering if that should have been replaced too? I also think that it might be the same spot where they slipped last time, any ideas why it might have reoccurred?

Cheers

It is good practice to lay a width of underlay along the valley and then overlap the general underlay on each side of the valley over this.

Yours has been holed

Thanks, that makes sense that they should overlap. In my case it's deteriorated so doesn't overlap any more. Had a roofer out and he never mentioned fixing the felt at all, i'm going to get another guy out. Since I had problems a few years ago in the same spot i'd like someone to be really thorough and not just push the tiles back and call it done.

tell them what you expect