Bosch WIS24140GB – unlisted error code 4 & 2/3/4

Hello – bit of a mystery here

My Bosch clothes washing machine
E no. WIS24140GB/14
is beeping and flashing one LED in the Spin speed column (#4) and three LEDs in the far right column Rinse/Spin/End – no’s 2/3/4

This error code is not listed in the manual and I can find no reference to it on this site or otherwise online.

The closest error is “inlet filter”, but that would be #5 in spin speed column (which is Rinse/hold) and 2/3/4. This refers to the inlet filter, but the machine fills quickly (and the error does not quite match, my error is #4 (not #5) & 2/3/4, inlet filter is #5 & 2/3/4).

Or there is the water in the base error – again not quite what I have as it is #4 (which matches) but only 3/4 not 2/3/4 as I have! And upon removing the lower front panel, it is as dry as a bone. I also checked the lower filter/trap, which had a tiny nut (from a pocket) but was otherwise clear. The pump impeller turns as expected.

The machine appears to be functioning fine otherwise.