I had that vibration in 1400-1600 rpm, part throttle acceleration. I just removed the heat shield and bracket altogether and it eliminated the noise. As far as I can tell I can't see any cracks in the legs that hold the shield up, although I only have 2 of those little pads between the heat shield and the bracket (whereas the TSB says to install 4 pads, 1 at each corner). SO perhaps it just the missing foam pads.
When I have some time I may try to diagnose a bit more...
Links to the TSBs
The latest bulletin from Land Rover states to remove the bracket all together.
A revised heat shield is required for 2017-19MY vehicles with V6 3.0L S/C Petrol; 2018-19MY vehicles with V8 5.0L S/C Petrol - only Transmission heatshield (LR106479) is required.