I had two pairs of Harbeth P3's. They were wonderful. I bought the second pair after I bought the first sound unheard and used them in different rooms. I have since replaced both with larger Harbeth speakers. But, believe me, you will not find much agreement with your assertion that the Harbeth speaker is "essentially the same" as the Spendor. It isnt even the same as the new Harbeth HL-P3ES. They are, however, the same size.
You could order HL-P3ES's from Wintertree Audio, or find the Spendors in a store near you maybe. The Spendors even come up used here once in a while. New or used they are less expensive than the Harbeths. The Spendors have been well reviewed and a lot of people like them. They should be fine little speakers. I remember seeing someone posting on AA, however, that he had sold his and gone back to LS3/5a's. I cannot imagine anyone who has ever had Harbeth P3's doing that.
The Spendors are easier to drive. The Harbeths require more and better power. Not a good idea to use them with a bright source or amp. The P3's are near field monitors, but unlike most such monitors do not have a dip in the presence region. They are flat through 20khz. They also have really wide dispersion. To use them, you need to keep them away from reflective surfaces like sidewalls and mirrors or glass cabinets. Ceiling reflections can also be a problem if you sit too far away from the speakers.
