Washer dryer stops mid cycle

I’ve gone through the forum but I didn’t find anything that really matched the issue that I’m having. I’ve put this in the washer section as the cycle doesn’t get as far as the drying cycle.

I’ve got a Waltham WTLS75WAV14 washer dryer. Whenever I use it it stops mid cycle. It will fill with water, get soapy, and slosh things around. However at some point it will go from saying that there is still X minutes left to just saying that it’s finished. No error codes etc. It doesn’t get as far as spin, and I think doesn’t rinse either. If I put it directly on spin then it will spin no problem, the same for rinse, or dry. So each function works correctly, but it won’t move through the full sequence. However there is one function, “easy maintenance” (it’s written in French), that works perfectly. The machine goes through the whole cycle and washes the clothes exactly how it should.

All the guidance etc that I’ve seen gives suggestions for what to do if the problem is consistent across all cycles due to a bad sensor, switch etc, but not what to do if one works normally. Does anyone have an idea for what might be causing this? A replacement control board is pretty expensive so I don’t want to start replacing things like that unless it’s god a good chance of fixing the machine.

I can’t find the user manual online, and there doesn’t seem to be any way of contacting the manufacturer. Waltham is apparently owned by Vestel, but even they only have a postage address and no mention of Waltham on their website.

Thanks for reading, and for any advice.