Our Bosch had been complaining about low water pressure, was stopping at random, and had taken it into its head to heat the rinse water.
The Bosch man came out and showed that although we had plenty of pressure (3 bar), the actual flow rate through the inlet hose was pathetic. Replaced hose and all is well.
In terms of symptoms, I could understand its complaint about low pressure since here, from time to time, mains pressure suddenly drops to 2 bar for a couple of days. But the other symptoms made no sense at all.