I’m getting a clunk in first gear if I goose the throttle from a stop. It’s like a firm clunk I can feel with my feet,butt and hands. Car drives perfect otherwise and won’t do it in other gears.

First thing to check is the fluid level. These gearboxes don't like low fluid, even by what seem like small amounts.

It’s bad engine mounts or a mount, took a video of engine moving under load sitting still. I’ll throw in the RR mounts and problem solved