If the current sound doesn't sound right, personally I don't think spending more money on a 252 or 52 will resolve the issue.
Good luck.
Whatever happens, I'm going to find a way to make the 282 work!
Don't forget you will need a good few hours between changes to let the amp /preamp settle down and warm up
That could be part of it too, and something somewhere might be running in. For instance, the DIN to XLR cables for the 300DR were still in a sealed bag. I'm not sure what the previous owner was using, something higher end?
I adjusted the speaker positions yet again, must have shifted it about 20 times now! This latest shift seems to have helped a lot. I just listened to an album by Sarah Jarosz, World On The Ground, and (with grudging admission), it did sound very excellent. It's rather acoustical, delicate, with prominent vocals, and the 282 conveyed this all with aplomb.
It's dawned on me that this huge jump in amplification has a very different presentation to the SN2. I'm not used to it, and it's hard for my ears to interpret. The SN2 gave a very enjoyable sound. Obviously it would lack detail, resolution and accuracy compared to higher levels of amplification, whether from Naim or another brand.
I'm not sure whether it was the last shifts in speaker position which helped, or settling/running in, or ears adjusting, but vocals seem to come up better now.
Also, my system seems to have become ruthlessly revealing. I tried a couple of tracks from the second album from Cable Ties, a modern punk band. The mix is really funny, the very low bass frequencies are missing in action. On my system now, I can clearly discern the bass and kick drums, but boy does the missing low bass make it sound rather strange.