Beko DW603 not fully draining

I have a Beko DW603 dishwasher and it’s not draining properly. When the cycle finishes there’s still a load of water in the bottom of the washer.

When I initially start it on a cycle (knowing there’s water in the bottom from the last run) it does start the drain process but only for about 8 seconds. If I want to empty all the water I need to hold down the start/pause button to reset, then turn it off and on via the main button, select a program again and repeat about 10 times!

I’ve taken the bottom front panel off and the under tray did have water in it but not sure how long it’s been there. I dried this and set it on another full cycle. There were no leaks in the bottom tray but still ended up with water in the machine as above.

The waste of the machine is plumbed into a waste disposal unit so I can see the water is draining when the drain pump is on.

Any help greatly appreciated!

Nigel.