I have been struggling with water consumption for almost 1 year, the cylinder head was not cracked, it was pressure tested.  It looks like the cooler will be the culprit, before that I bought a disassembled one and it turned out that even though we tested the pressure to 4 bar it was not enough.  The water escapes at 7-8 bar.  In vain, the pressure in the engine is 1.5 bar.  It will be clear on Tuesday whether the error will be resolved.

Good point, however I am selling back to the trader I got it from for a small profit. They told me that they could not find a leak 1 month after I reported the issue to them after buying it and sent me on my way. I then over the course of ownership had the EGR cooler and Air charge replaced with no affect. So part of me thinks they knew at the time of sale this was an issue as the car was bought a few thousand £'s below value at that time.

The whole car is worth about £4500 now so not very economical to get it repaired. Especially as as the cost of the previous 2 part changes didn't do the trick.