I'll chime in though celticsfan1 has more experience relative to your specific question. I had the Harbeth Compact7ES's for several years and have heard the SHL5's at least twice. I now own the DA-1.1AP's but have not heard the DA-RMa's. So, take this for whatever it is worth.....
I really like the Harbeth sound--one of the best speakers out there IMHO, particularly for vocals, acoustic instruments and small scale music (chamber, choir, jazz vocals, etc.) In fact, I moved into a larger space and shopped dozens of speakers for almost two years and could not find anything that sounded as "right" to my ears as my C7's. Yes, the larger speakers went deeper, several were more dynamic and quicker, others had a bit more realistic high frequencies with more air and sparkle. But none got the critical midrange right and presented the music in a seamless way like my C7's and so my search continued....and then I found Daedalus. I think Lou's speakers get the tone right and then add to that all the dynamics, speed, clarity, spaciousness and ability to convey the power of live music that make things so engaging and so real. So, while I have not directly compared the SHL5's and the DA-RMa's I'm guessing that even without the AP crossover you would find some improvement over the Harbeth's, though I don't think we are talking "wipe the floor with them" kind of differences. The Harbeth's are excellent speakers. The Daedalus models are for people who really like the Harbeth "tone" but yearn for a more complete package and all around speaker, one that can play ANY type of music and make it sound live in your room. Hope this helps despite my caveats above.