Whirpool ADG7550 not draining-changed the pressure switch

My ADG7550 has stopped draining. If I start the wash cycle, it stops after a while and flashes four times which indicates drain issues. If I then put it on a rinse cycle , the pump will drain the water, so that works.

I replaced the 3 tag pressure switch as searches on here suggested that was the likely problem, but still doing exactly the same thing.

Any ideas or is it time to get the credit card out.

Thanks in advance.