Bosch washer dryer drying issues

Hi everyone,

I have a Bosch washer dryer WVG30461GB.

Recently drying started to fail - after a "Gentle dry" programme, I will find the clothes hot and very wet - arguably more wet than they were before I started the run. The machine initially says the programme will take 2.5 hours, however I noticed that when it gets to ~30 mins remaining, it will put more time and it will actually take 3 hours in total.

I checked the pump filter and it seems clean. Also, there are no error codes. One repairer I called said that probably too much fluff accumulated since I did not really know I was supposed to run the drum clean programme often. And that fixing it now requires disassembling the machine, which is a 350-400£ job. I tried running the drum clean programme multiple times now, but it does not seem to bring the drying back.

I wanted to ask for a second opinion here, or if anyone has had this issue before.

Thanks!