I owned the baby Spendor 3/5R's, and played them in a very small 11.5' square den. I had great success with them in that little room. I auditioned Harbeth P-3's in a dealers showroom, that was likely about the size of your room, perhaps a bit larger. I can't help with your specific question, but did you feel the 30.1's filled your room pretty well. The 3's certainly didn't at the dealers where I heard them. One more thought would be the JMR's are supposed to be more tube friendly, if that matters to you. I bet those 30.1's are wonderful.
Harbeth vs JM Reynaud
Hoping for some input. I come from a Spendor perspective (my daughter recently inherited my BC-1s) and currently use Spendor s5e's with a Unison Unico hybrid integrated amp. Sound is wonderful. I have seen all the discussions/reviews of Spendor, Harbeth, Stirling, and ATCs, and I am partial to getting the midrange 'right' (the 'BBC' sound). With a 60th birthday coming up, I've been looking into one last speaker upgrade. With all the rave reviews of Harbeth's, I got to spend some time auditioning the Compact 7's, M30.1s and Super HL5's (not the plus). All sounded great but the 30.1's really seemed like something special. I was able to take a pair home for a weeklong audition, and truly fell in love of what these do. So now the problem. I have recently come across a several reviews of JM Reynaud speakers, including some recommendations on this forum as an alternative to Spendor and Harbeth. These really look like possible option for the BBC sound, but there is no opportunity for an audition, and that's a lot of $$ to buy completely unheard. Can anyone provide some thoughts feedback on how the JMR Bliss Silver or the Offrande Supreme's might compare to the Harbeth 30.1s or Super HL5 plus? My living/listening room is 15 x 25 (speakers on short wall), hardwood floors and plaster walls.