Freelander 1 fuel gauge

Hoping someone can help me with a problem with my 2005 td4 Freelander. Been perfectly fine until last week it lost all power and was black smoking, asked a friend to have a look at it. He said it could be the unit in the top of the tank playing up so he took it out and replaced it with a new one over £50.. Bought it back, no different, not only still no power but now the fuel gauge shows full when empty and the empty when full, needle works opposite to what it should.
Had a look myself and found a split intercooler hose, replaced it and she's running spot on again. But.. Still the gauge is working backward, I've taken the sender unit out of the tank and refitted it myself, tried swapping the two wires over in the connector, still reading full when I know its empty, and when I put £15 diesel in it went down to 3/4 full. Any help much appreciated. James

This has been discussed on here before - there is an answer that I don't remember but you could have a search for it.

However, can't you simply put the original back in? It'll probably last longer than a £50 aftermarket unit.

Earlier fuel senders work in reverse of the later ones - refit the original and all will be fine.

On that age car all it does is the fuel gauge and fuel pick up - the fuel pump is remote on that age - so that’s £50 that didn’t need to be spent!

Thank you ever so much for your help, wish I'd had a look at it myself now in the first place but I didn't have time. Shall put the old one back in tomorrow and hopefully will be back to how it was. Thanks again