Rob will probably be able to answer this question due to his investigative abilities. In the workshop manual there is a procedure to adjust the steering lock stops, I quote
“Steering lock control is provided by lugs forged on the axle beam. These stops may be reduced by filing or built up by welding. To avoid the necessity for welding,steering lock stop, Part No. C.1405, is available & is fitted under the swivel pin nut.”
Does anyone have a picture, diagram or a description of this part C.1405?