That's decided then, it's relocating from the garage to the cinema room this weekend. Not looking forward to untangling the spaghetti junction of wires at the back of the current cabinet. Wish me luck!
Thank you @Bl4ckGryph0n. Appreciated. Yes, I am pleased, esp. as I'm not a DIYer. I have got the bug now. I want to build something else!
As for Ikea, I did spend an inordinate amount of time, years! looking at options. Just couldn't find the right one with the right dimensions.