Bubblecar said:

Well the coiled metal drain cleaner thingy has arrived and I managed to push it down the drain, but it didn’t pull anything out. It’s nearly two metres long.

Not sure what else I can do with it. It might have dislodged some muck but the drain still seems blocked. I’ve poured some more crystals in and will see what happens.

Do you have an outside drain you can try, near the bathroom perhaps