Upgrade from Spendor SP 1/2, what's next?

I've had the SP1/2e for 10 years and run them with many amps. They always deliver musicality. Had the with Naim 135, 72 and loved it........until I used an old Scott 299 while the Naim gear was in the shop. At this point, I use the Spendors with Radio Craftsmen c500a. It is amazing how loud 10 wpc is on the Spendors! The nicest thing about these is that you will love them with whatever amp you have now as they are not a demanding load, but if you ever buy something better, the Spendors will deliver.

Neither are floor standers, but your obvious progression is Harbeth next, then to Audio Note.

Don't know if the OP is still looking but I had the Spendor 1/2E's in my system for about 4 years and they are excellent speakers with really only one weakness - they don't do the bottom octave. Since I listen to classical music (lots of orchestra) the bottom octave is essential for the most realistic sound. I tried and tried to get a subwoofer to integrate but was never successful. So, my upgrade was to Vandersteen 3A Sigs. The Vandy's do everything the Spendor's did in the mids and high (i.e. supremely natural and musical) but add the missing bottom end that the 1/2's didn't render. I've had the Vandy's now for several years with no urge to change.

...but your obvious progression is Harbeth next, then to Audio Note.

Or maybe to Reynaud.

Sonus Faber Cremonas, Harbeth Super HL5, ProAc D25/28, Quad ESL 63