Flashing over waste pipes leak

[PeteTown]

Hi All,
My Grandads house has an veranda out the back that goes under the upstairs bathroom. The waste pipes from the sink and toilet then head down into the roof. This appears to have not been flashed correct. See image below. Could you recommend the best way to fix this? I was going to see if I can get the flashing under the pipes and do some sealing with liquid rubber. It may also need a pipe flashing fitted?
Thanks for your help!

Pete

 

[catlad]

What a mess try acropol

 

[Burnerman]

Lose the flash band, and post back with another pic, can you?
John