Hotpoint LTB 4M116 integrated Dishwasher stuck mid-programme

Hi, I have had this dishwasher for perhaps a couple of years. It has been trouble free until yesterday. The program appears not to have finished: the on/off light is flashing rapidly and the ECO program light is on (not flashing). When I push the on/off button the lights go off but only for about 3 seconds. A noise then appears from the sump area . The sump is empty. I have taken out the filter and cleaned it although it wasn’t particularly dirty. There is a very small jet of water bubbling out from the 9 o’clock position of the bottom of the sump; this appears to be making the noise.

I am stumped because all the error codes that I can find on the internet don’t show the control panel of this model. I have tried holding the on/off switch down for a long period, but the noise and the jet of water start up again. I can’t even switch it off because it starts up again on its own. I have also switched it off at the plug but when I switched back on, the problem resumed. I have a ten year parts cover from Hotpoint so only have to pay labour but fear that this could be high. Any help/advice would be welcome. Thanks.