Leaking Roof - Any Help and Advice needed! Thanks

I have had a leak since October through my bathroom ceiling (which is a series of wooden planks). It is a top floor flat in a converted Victorian house so the roof is directly above. The roof above the bathroom where the leak is is a flat roof which also houses one of the water tanks (on the roof!). The leak was minor until this month and only leaked every 4 weeks (a small drip). However it now leaks every time it rains - thankfully into the bath itself. It has taken an age to get the builder/roofer round (who is trustworthy although unreliable) and finally he came last week. I went on the roof with him and it doesn't seem in too bad condition (which he agreed with). The area above where the leak is has some moss and seems more worn. The water tank housing also has small rips in places and the lid felting has worn away so there is exposed sodden wood. The roofer feels this is the problem and intends to fit felting around the tank case and cover the surrounding mossy damp part of the roof. Does this sound like the cause? I am concerned that I will pay him to do the work and then the leak continues from elsewhere. I know that water can travel but it seems too much coincedence that this is above the area.

Finally the builder can not make it this week to fix it and it will probably be next week earliest that he can fix it. I know there is yet more rain forecast which means more leaking (it leaked the amount of 1/8th of a tumbler during Sundays 24 hour spell). Do you think that it will be okay to wait until next week without causing any serious damage (and risking the roof collapsing)?

Worried and damp from Woodford

hi,
shouldnt think your roof will collapse!.

once your contractor has done your roof repair get him to give you a written guarantee on works done.
if he wont get someone who will.

The water tank lid needs to be totally intact. Also if the tank is sitting on timber bearers on the roof, the weight of the water can cause the bearers to cut the felt in the summer. I've done a few houses around Woodford/Buckhurst Hill etc, and they all had similiar issues with tank lids, usually soaking the strammet (straw) insulation and running through the deck.