Roof leak detection - recommendations?

[TinyTear]

We have a leak in our second bedroom / office. it has been there since we moved in 2009 and I think it had been there before we bought the place as the staining in the carpet (cleverly hidden in viewings) is in the right spot.

The layout of the place means that above that room is a sloping roof and our livingroom (upside down maisonette). we changed the balcony doors and it helped for a while (the wood bottom bit was rotten) then it came back again and we sealed some bits on the roof, and then finally we got a roofer in and he did something to that bit of the roof... and didn't work...

Whenever it rains it's drip drip drip... we now have permanently the travelcot filled with towels to absorb any water and two buckets (which are catching all the water, the towels are in case it gets worse)

Can't get guests to stay in that room if it rains (and we know how it's been lately) and can't work from home in that room as the drip drip is so annoying i tend to decamp to the kitchen with the laptop...

We now decided to pay ourselves for a leak detection company to find the root of the problem and then getting it fixed will be shared with the other flat owners in the building...

We found some online and got a quote from one, but would like to know if anyone has used these companies and has any recommendation.

Most of the google results for leak detection are for pipe and gas leaks, not roof ones... any help? Thanks

We are in London (in case it helps)

[TinyTear]

Bump?

Or drip...

[lessonsintightropes]

We've had a couple of roof leaks in different bits of our flat, and just got a regular roofer round who made some minor flashing repairs and replaced a tile or two. I'd start off with a basic roofer repair and see where you go from there. We found rated people was a good place to start before we got some personal recommendations.

[OnePlanOnHouzz]

I used food colouring to find out where the water was coming in on our flat roof - then just got that bit fixed - much cheaper than having the whole roof re done ! ( I'm such a cheapskate !)

[TinyTear]

lessons we had someone do a basic repair and it did nothing... and it seems the people we bought it from had also done something and didn't fix it... that is why we are going for this solution.

oneplan good idea on the food colouring... the main issue is that it's not a flat roof and it would be a lot of roof to cover to find out where this is coming... might have a think about that if we don't find anyone to do it...

thanks

[TinyTear]

Just a small update, we found a leak detection company, they came last week and it's not on the roof, it's actually on the fascia boards on the balcony/dormer and it seems there is some leak where it joins the roof, but the roof is ok...