John Lewis WD1480 stopping at the end of wash cycles

Hello. We can’t afford to get an engineer out unless we have no other choice. We’ve got a John Lewis wd1480 and it’s been utter rubbish from the start. Now out of guarantee.
The latest problem is that when it gets to the end of the wash cycle and drains and tries to spin some of the soapy water before the rinse cycles it starts banging about violently and then grinds to a halt. I have to put the washed but not rinsed washing through the quick cycle and fast spin it. The drier bit works fine. It occasionally runs a cycle from start to end but not often. The quick wash cycle works just fine as does the wool cycle. It’s the cotton and synthetic cycles that don’t work. Well at least the wash bit does…but then it doesn’t get any further. I can run a fast spin no problems. The pump is working fine. The machine is perfectly level. My husband is an engineer (though not of washing machines or driers) so he’s had a look. he thinks the dampers seem ok, the main drive belt ok and beyond that he can’t see.
If we can possibly fixe it ourselves we have to. Can anyone advise please?
Thank you

PS no error codes. The machine stops and the digital time left displays how much of the wash wasn’t completed. With previous problems we got codes.