Sorry - I got the name wrong. It is called the container light, the one above the filter light. But of course, the container is not the issue, because of the modification to vent to the drain.
Okay - I may not get to this now, until Thursday - work demands. But I think I can follow that through. Will get back to you, then.
Well, I tried that but ran into difficulties getting at the water pump. I wasn't able to find a way of removing the plastic cage that houses the pump without risking breaking it. I did manage to get at the sink underneath the condenser housing (it's just beside the pump) and suck out the water, but after three lots of washing, the container light came back on and I have not been able to sue the thing, since. Have you any advice on how to get that housing off the pump? Will it matter particularly if I snap any part of it and repair with (say) insulating tape?