Fuel gauge problem

I am doing a chassis replacement on my Defender110 300tdi. The chassis is a tdci with 300tdi mounts, so fitted a tdci plastic tank, this is where my problems started. I was told to use a disco 1 sender unit which I have fitted but now the fuel gauge doesn't work, since been told sender unit is not compatible with defender clocks, also told ROW spec wouldn't work. Anyone done this conversion, what did you fit to get the gauge to work, thanks in advance

You need WQB100430 or WQB100440. These will work with the TD5 fuel gauge. I personally fitted WQB100440.