I have a new 2018 model BDR with the standard tank and the awesome access hatch on top in the floor of the boot.  Its got the tube-type fuel lever sender unit.  The fuel gauge is very inaccurate and move around quite a bit during driving.  The friendly guys at the Backdraft factory in Durban sent me a Fuel Gauge Wizard (
https://www.spiyda.com/fuel-gauge-wizard-mk3.html) to normalize the needle movement.  They included comprehensive instructions to install it and I did the connection properly.  However it does not have the desired effect.  Needle movement is still about a quarter of the range during driving.  Any advice?