I dont think there was ever any bolt in conversions, the mobility cars were sent off to a company called chairman i believe and they modified them.
i tried ringing them but they couldnt help me.
also the power steering conversions that were on some mk4's were also highly modified.
my rack came from an orion with the conversion and there was another rack there off another orion but they are nissan racks and are nothing like bolt straight on.
as before, forget about it, its far too much work.
plus the less people who have it the more rare my one is lol