l322 Transmission interface bus fault

Hi Many thanks for letting me join the forum. Hopefully one of you kind people might be able to help.
when I start the engine I have the park mode displaying as normal on the dash. As soon as I move to put it in to drive of reverse nether the R or D show up on the display and I get a Transmission interface bus fault showing. I put back into park turn the engine off and restart in park. P shows up as normal and no fault. as soon as I put into drive the fault appears again, no D or P showing. I have driven the car but it does not change gear
Many thanks
Dave

Hello and welcome
best to ask over in the range rover section of the forum https://www.landyzone.co.uk/forum/range-rover.10/
And saying hello in the intro section is good form.