Finally, Pete, I found the question.
Let me tell you this. If you can ever get a dyed in the wool Lydiard person to talk with you about specific paces or heart rates, you know that you're not talking with a dyed in the wool Lydiard person. It really is something you're supposed to learn to feel and this answer will be pretty long.
Ron Daws did a lot of his distance work at around a 7:00 pace. So, I'm told, did Bill Baillie. Peter Snell told me that at the start of his build up phase he'd do the 22 miler at around a 7:00 pace early in the year (on a very hilly course) and work down to a bit above 6:00 at the end of the phase. The shorter runs were a "bit" faster he said, mentioning that by the end of the build up he'd be doing 10-12 milers at about a 5:30 pace. Peter actually believes that once you're running much slower than 7:00s the usefulness of the run declines, but that's Peter, not Arthur. Jeff Julian did a lot at 6:30-7:00 pace, but Mike Ryan (not to be confused with Kevin Ryan) was evidently below 6:00 pace much of the time. But before you wed yourself to any of those paces, remember that all of those guys were world class runners capable of going much faster for a long time.
If you follow Arthur's quotes on this you find a bit of self-contradiction, e.g "good runners rarely run slower than 7 minutes a mile," and "what an LSD runner can accomplish in two years maybe we can do in one," and (to his guys in the 60s as they ran the Sunday 22), "You're wasting your time if you're running slower than 2:20.
But he also told me once, "Don't think about minutes per mile. Think about staying comfortable." And in "Running to the Top" in discussing base training he says, "You can never run too slowly, but you can run too fast."
So that should sort it all out, eh?
If not, here is the one thing that he has said consistently over the years and Peter Snell told me the same thing; that the trick is to be able to get out each day and do the run that your schedule calls for. If you run a 20 on Sunday at an 8 minute pace and planned to run 10 on Monday at a 7 minute pace, but are often unable to do that Monday run, you went too hard on Sunday, or perhaps on Saturday or Friday. If you can manage the 8 minute paced 20, the minute paced 10, Tuesday's 7:45 15 and so on, you know that you aren't running too fast. But are you running too slowly? The only way to tell is to rachet the pace up a bit. If you still can maintain the desired pace and distance day in and day out, you still aren't going too fast. It's too fast when you need real "recovery days."
So you want to run as fast as you can within that framework. But I think in recent years, Arthur, like Hadd, has become aware that people tend to overestimate how fast they can run aerobically and tend to push too hard, making fast aerobic runs into slow anaerobic runs, hence the quotes like "You can never run too slowly," etc.
Yes, the steady state is very much like Hadd's runs where you go as fast as you can for an extended time without having your heart rate creep up during the duration of the run. The difference being that Arthur puts very little stock in heart rates and would describe the steady state run as one where you go as fast as you can without feeling your tiredness or breathing rates increase as the run goes on.