We have an ensuite from which the waste from the shower tray, wash basin merge (I assume) with the toilet. Recently when we flush the toilet it doesn't quite run away like it should, the water following the flush settles maybe 2-3 cms above normal and then subsides to normal in 15 seconds or so, while this happens the shower trap bubbles a little.
The toilet itself does not appear to be blocked.
I've tried blocking the basin waste and overflow, filling the shower tray with water and then using a plunger and it seemed to help a little but hasn't cleared fully. Repeated the above a few times while also flushing toilet and releasing a full basin.
Is there anything chemical we can put down the waste (and which one?) to help shift whatever it is that's getting in the way or do we need to stump up £££ for someone to come and sort it?
Cheers, T
