Advice regarding streaming please.

I own the Audiolab 6000N and I'm very happy with it's build quality, streaming features and sound quality With it's user interface I can control all streaming services (there are many) through the DTS Play-Fi app using my smart phone I do use an external DAC the Exogal Comet Plus, but it does come with respectable internal DAC

Don’t get me wrong, the Audiolab is not a bad streamer, but I know the rest of the gear is capable of better. 

Streamers make a difference.
I used Mac Mini, AURALiC Aries G1 and Lumin U1 Mini. I prefer the sound of the Lumin. Hideous app though so plan on using Roon or Tidal Connect f you stream Tidal or I guess it may be semi usable with an iPad. 
Use a good USB cable (they also make a difference) or a good AES/EBU cable depending on streamer and DAC resolution capabilities. 
 

The streamer is rarely the weakest link. If you are comfortable with the user interface I wouldn't bother changing it. If you're simply looking for something new that's a different story. The Kef R3 are good speakers but could use a subwoofer to fill in the low range or new speakers that extend lower, you'd notice more difference looking there. Get a measurement microphone and REW see about optimizing room treatments or using DSP. Any of those will affect your sound exponentially more than changing a streamer. 

+1 @djones51  At a certain point, this hobby stops being orgiastic buying and becomes something like work, but the fun work one puts into a puzzle or project. If one is not prepared to do that work, then an endless cycle of buying, selling, and posting awaits thee. To each his own.