I did away with the railco bushes and replaced them with tapered bearings (like a Defender). The swivel grease just doesn't lubricate the bushes - as you know).
The series lower taper roller bearings drop straight in to the railco hole and don't need greasing more than the swivel grease does. You need to turn the trunnions down to 19mm to fit the bearings and then shim like normal. My steering is spot on now.
Further information is available on this excellent thread:
Series trunnions