You'll get contrary opinions about "which Harbeth model?"
I thought about but did not elaborate on a couple of things in my first post. First I had SHL5's and C7's in my previous home. Both are very nice. My previous home had a much larger listening room than my current home which is very close to the size room you will listen in. The 30/30.1/C7's are two way speakers and some amplifiers mate better with two ways than the three speaker SHL5's. I have experienced this first hand, so consider what amplification you pair with which Harbeth. Lastly I believe the revision of the old 30, the 30.1, to be overpriced at new price sold in US. Some will come to the defense of the 30.1 as worth every penny. I differ with Donjr in his use of the words "much more" as I've heard both and the improvements are more subtle IMO. The P3ESR's are wonderful speakers as are all current Harbeth's and easy to find used at big savings, but in your space or larger left me desirous of more bass as long as that bass is tightly controlled and bass notes are well delineated. The LFD amplifiers as a product line I know well, have excellent control over the Harbeth bass on all models. Consider your equipment pairings carefully as some amplifiers really do have better synergy with two-way speakers. If you want some more ambiguity on Harbeth owner opinions, checkout the HUG forum where the engineer Shaw himself described his 30.1 improvements as "subtle", but what does he know - he's only the designer.