Leak

The important question is: do you use the photo with the healthy 1.5 bar display or the one from 90 minutes later with the less healthy 1 bar display? Yes, the new boiler is in although its installation, like the installation of its predecessor has only helped to reveal other weaknesses in the system. There is a leak somewhere, exacerbated, I suspect, by the process of flushing out the pipework. It certainly predates the new boiler though it was much slower then. It has to be acknowledged that the guy who did the installation did his best to track it down even though it's not really his problem. His job ends with connecting the boiler. So that's the next job - find it. There aren't too many places it might be that wouldn't have shown up already as a wet patch on a ceiling or wall. Ground level, dribbling into the space under the floor is the most likely, but that does mean dismantling some of the kitchen. Joy.