I'm curious on how a Dyno Dynamics dyno is able to convert a 2000n or a 5000n or a 9000n torque value from a dyno run - into a nm value?
Or does a Dynamics dyno just do an estimate from the (n) value to create a ( nm ) value?

N is the force being applied to the roller from the surface of the tyre.
You need to multiply that by the radius of the tyre, in metres, to get Nm at axles, then you ned to divide by diff ratio to get Nm at tail shaft, then divide by gear ratio the run was made in to get you Nm at engine.
Nm (engine) = N * tyre radius / diff ratio / gear ratio

Thanks for that. Once I read the tyre specs I'll be able to have a go at the formula you provided.
cheers!