Gosh Grant...interesting information, and you must have been really upset. However, all might not be lost. Quick question: Did you do a test print at least of any of the images? One thing I noted very quickly is that the stain with Pyrocat is very misleading, and one might conclude that the negative in question is very thin UNTIL you make a print. The stain with RP is very impressive with lots of detail, etc. That green stain will blow you out of the darkroom! Looking at the same scene properly exposed and developed in Pyrocat HD is blah, blah, blah....UNTIL you develop the prints.
Can you give us some information about the time of development, and the temperature you are using? How about the exposure...you are certain that no errors were made ( we have all made them Grant! ). Are you using BTZS curves? If so, there is some great information on Ed's site about proper exposure based upon SBR, etc. I have some really fine TMax 400 negatives made with Pryocat HD and my Jobo expert tanks at 24C, and am about to venture forth with some HP5. We can discuss the relative merits of prints made with Pyro and other developers at another time, but for now let's see if we can solve the issues you have raised. Please do a contact print ASAP and let us know what you find Grant. Based upon the results we can possibly add some additional suggestions. I know Sandy will chime in, and he is THE expert of course.
Ed