Thanks Steven. I've never heard of Koi but did find this on a Google:
https://www.berklee.edu/berklee-today/fall-2001/Koi So looks like they may still be around in some form or other.
My own setup suffers considerably due to the need to accommodate the layout of our sitting room furniture and, in particular, the fact that I agreed to let my Mrs have a "hole in the wall" gas fire installed right in the best position for the TV. Although the sound stage is now compromised it's still massively better than listening to sound on the TV speakers alone. My present setup is the third I've owned. First one was a Shibuya which consisted of an Amp with radio receiver and 8 track player with 2 quite large speakers which were separate from the Amp. Back in the '70s - when I bought it - it was a pretty reasonable stereo package deal. It now lives in my garage workshop and I listen to it if I'm doing something which takes more than a few minutes. Next I bought a Sony "all in one" surround sound system which consisted of an amp with front and rear speakers. It was a massive step up from the Shibuya but lacked a centre front speaker and subwoofer. Then probably, about 15 years ago, our TV packed in and we replaced it with a decent Panasonic which does 1080p HD pictures - not spectacular by todays 4K standards, but pretty impressive at the time. As it did HD I decided to get a Blu Ray player to go with it and started building up my Blu Ray collection of SF movies. Of course a lot of these I'd seen in the cinema so knew that the Sony setup was missing out quite a lot of the sound detail and effects, especially the bass.
After a while I started wondering just how close to the cinema experience I could get with a decent setup which didn't "break the bank" Took me several years of dithering research to end up with my present setup which is a Yamaha RX A810, Two large bookshelf front speakers and two small bookshelf for rears with a centre for speech - all Monitor Audio Bronze and an active sub by M.J. Acoustics. It's all I want and I'd no intention of replacing any of it. However, unfortunately, the Yammy receiver has decided it's had enough and, as it must be around the same age as the TV, probably not worth repairing. I'm trying to decide what to replace it with - I'm about 90% of the way to deciding on another Yamaha, probably the RX A2A although it is reported to have HDMI passthrough bandwidth restrictions which won't affect me as I'm not a Game player. It's a model which has been on the go since around year 2000/2001 and has benefitted from several upgrades, which I quite like as it must be pretty well sorted by now. I'm guessing it's about due to be replaced by a newer model so hoping it may turn up in after Christmas sales at a good discount.
If it interests you here's the amp/receiver I'm looking at:
https://uk.yamaha.com/en/audio/home-audio/products/av-receivers-amps/rx-a2a/ It's not the ideal choice for many and has some shortcomings, but gets very highly praised for it's cinematic sound, which is my main interest.