M
Minty!!
I thought that might be the case, hence the question. The boiler installer has stress-tested the system because he couldn't be 100% sure of the pipework he was connecting on to. He's found a leak and the responsibility is clear. A few weeks or months down the line and boundaries get blurred in terms of who's liable for problems caused by the leak.
The pressure testing that you previously mentioned - are you sure it was at mains pressure?
Definitely mains pressure, the system was connected directly into the mains water supply for four days. Thank you for your input into this matter, l feel a lot better now knowing the installer was not in the wrong pushing the system so hard and the boiler has been caused no lasting damage. Cheers!