Smeg CR330SE fridge-freezer defrost drain blocked

I’m trying to help a neighbour whose built-in fridge drainage is blocked, so she keeps getting a build up of water.

I’ve “rodded” the drain tube as far as I can go (and a lot of gunk came out) using some mains cable that fits the tube perfectly. However, it gets stuck quite a long way down and I don’t know whether this is really the blockage or some bend in the drain pipe.

I can find various exploded diagrams online, but cannot see one that shows the drain tube and evaporation tray.

Obviously the easiest and best solution would be to just pull out the FF, but it’s in an awkward position and I’ve just had abdominal surgery, so can’t do the necessary lifting.

So I wondered if anyone knew a way of clearing this blockage without getting to the back. Is there a “kink” or some other restriction near the end of the tub that I’m trying to get past, or is there some technique of dissolving the gunk that wouldn’t cause a nasty residue in the evaporation tray?

If not, maybe I just have to wait until I’m fit

Thanks in advance