Leak Detection

I don't know any companies but Google does.

There are a few DIY options that escalate in cost:

• Start by introducing a leak sealer into your system. It is the fastest & cheapest option & just might work. Do you have a closed or open system? The leak sealer will potentially work in both but I ask because if you have a closed system you are probably seeing the system pressure dropping to zero bar. After introducing the leak sealant & topping up the system try running it at lower pressure so you don't blow out the newly formed seal. TEK7 do a product called "Plumb" available from most HW stores. I know for a fact Woodies & B&Q do it. Its about EUR35.
• Hot water leaks may be detected using a FLIR camera that you can attach to your iphone or android phone. They're around EUR250 & can also be used for finding & eliminating cold spots or draughts in your house. Google FLIR 1 or FLIR one
• I saw a you tube video where the guy introduces a strong bottle of perfume or after shave into the system. When the perfumed water leaked it gave an odour in the area of the leak helping to narrow down the location. THis might takes several days to weeks depending on the size of the leak & the depth of the pipe in the ground.
• Youtube is your friend for all the above options.
• Goodluck - I hope you can get it sorted without breaking out the kango hammer.