@signaforce I am a bit conflicted in recommending the KRELL 300i integrated or the KRELL Duo 175XD (I see my old one up for sale). The reason being that KRELL is a ___show as a company at the moment, so you are taking a risk. Though people like George Myer Audio in Los Angeles can repair KRELL. Since I am close to LA I would likely go with the KRELL.
I liked the KRELL Duo 175XD more than the CODA #8 v1 and the CSiB. I like the CODA #16 over all of them. I have not heard the new CODA S5.5 but it only has 50 watts (with curent) and I always want more power with KEF.
The amp I would like to experiment with you BHK preamp is the new SimAudio 761 from the North Collection. They may sound great together. It is a better Benchmark AHB2 to my ears. The AHB2 would also sound good with the BHK. I used the AHB2 with a Schitt Freya+ tube preamp and KEF LS50 Meta and I really liked it. Though the Freya+ was not my fav gear.