Henry:
1. Abruce is absolutely correct. Take the P300 out! It is probably choking the system a bit and also leaning things out.
2. Supporting equipment is fine. If anything else is questionable, just in terms of not being up to the quality of the rest of the system, I would say it is the Rega and the IC's.
3. Are you firing the long way or the short way in your room?
4. How far into the room are the speakers?
5. What are the surfaces like in your room (floor, walls, etc.)?
I read what Dolphin said and do disagree with him based on what I have heard in every customers system I have setup. I do not doubt what Dolphin heard, just as I do not doubt what you are asserting, I just do not know what conditions and what components were in the systems that he heard.
If you would like me to call you, I would be happy to see if we can get the system sounding more like what you expected. You own one of the most spectacularly lifelike products I have ever heard. Do not give up quite yet.
Email me your number, and I will call you upon my return from the HES Show on Monday.