Freelander hse 2.2 td4 auto gearbox problem

Hi, new to this forum, iv just taken on a 57 plate land-rover freelander hse td4 2.2 automatic which has a automatic gearbox problem, it starts up fine, gear lever selects gear, but doesn't move at all, revs up fine like it should, no movement forward or reverse, no warnings on screen, I initially thought gearbox, then someone said its more likely the cable, and when I looked into it I saw the gearbox ecu so that has come into my mind, so if anyone has had this problem or knows what is wrong and what needs replaced I'd appreciate it, gearbox, cable or ecu, or something else.

You need to run a diagnostic on the TCM, or you'll just be guessing.

I think il be breaking it for parts tbh, after more investigation there's too much corrosion underneath, no idea how it's passed its mot like that, I won't be spending on it.