Chimney/roof leaking advice needed :)

[renovationtimes2]

Hello,

We had new led flashings fitted. We seem to still have leaks coming through around the chimney- the roofer has returned 4 times to try to remediate but it's still leaking somewhere and we're not sure where/what to do. Please see pics. We're also not sure if those wet patches on the timber are drying out or still getting wet.

We had the following quotes to help the issue. The 1st quote/roofer wants to completely remove the entire back flashings (he said they're not great) and start from scratch, so he can give us a guarantee, and re-point the chimney/flaunching. Obviously re-doing them all feels expensive and we're unsure it's fully necessary as it's only leaking around the chimney, but keen to hear your thoughts.
I've attached a picture of the quote.

The second is our lime plasterer (who is trusted and we have used before, but not a roofer), who has quoted us the below:
To remove existing flaunching on both stacks and existing pointing on rear chimney. Re-point back chimney in Natural Hydrulic Lime 3.5. Re flaunch both chimney caps in Natural Hydrulic Lime 3.5
It needs a brick at the back and then a seat/flashing sat at the back which I can do with GRP trims. And bitumen flashing if needed to rear chimney where parapet meets the stack
Dispose of waste. Including materials
£1900

We are leaseholders and somehow need to get downstairs to agree to contribute to the cost of this, so any advice on what's best will be super helpful!

Thank you

 

[noseall]

Looks to me like the side flashing need to be tucked under the tile above rather than on top. It's poor though and a amateurish back gutter.