RA,
Not sure what you are basing your facts on, and why you are so down on Yellow Gate, but for your information ...
Yellow Gate was never designed for low level operations in Nimrod MR2, it was originally the RWR from the F15A, known as Loral 1017A. If my memory is correct it was destined for the Nimrod AEW 3, hence it being fitted to the E-3D, in addition to the MR2.
Yellow Gate is, and always has been, an RWR processor that has been programmed as an ESM search system for most of its life on MR2 and E-3D.
The major limitation of Yellow Gate is not the processor but the aerials which give poor/unreliable direction finding.
Y_G